The Ultimate DIY Rocks!
- Thread starter JohnL
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Not mr. wilson but but I have a little bit of experience with public aquaria as far as building them goes. I worked on Seaworl of San Antonio during the initial construction before the company I was working for got kicked off of the project :rollface:
They used tons of epoxy coated rebar for the main structures and pools. I wasn't there to see how it was finished but the plans showed them to shotcrete over the initial structure in the Reef House. I'm not quite sure how they covered the final product whether they used some type of fiberglass overlay or molded concrete and painting.
Robert
If you ever want to see something unbelievable dig up the video on the net of them craning Shamu and clan into the giant tanks they have them in.
mr.wilson
.Registered Member
I worked on a 50,000 gallon aquarium at a private residence that used 24" deep walls with a substantial amount of rebar. It was a freshwater application, so it was regular steel rebar. $tainless $teel rebar would be required for a marine application.
Structural concrete is vastly different from the stuff you read about in this thread. It requires larger size aggregate, with a lesser amount of portland used.
You would need to construct plywood forms to hold it together as it sets. Wet concrete is very heavy, so it needs to be a substantial form. Water-proofing is another process. You would have to coat it with several layers of water-proof parging such as Quikrete "Quikwall", or Thora "Thorite".
Concrete may be cheap when you're making a few rocks, but the material costs add up when it's a structural project. A plywood and epoxy structure will cost the same or less, and will require less labour (although still a lot of work).
The other issue you will come across is the weight of the finished project. Supporting a 1000 pound aquarium is one thing, but another 1000 pounds for the stand and sump might sink your battleship right through the floor.
Structural concrete is vastly different from the stuff you read about in this thread. It requires larger size aggregate, with a lesser amount of portland used.
You would need to construct plywood forms to hold it together as it sets. Wet concrete is very heavy, so it needs to be a substantial form. Water-proofing is another process. You would have to coat it with several layers of water-proof parging such as Quikrete "Quikwall", or Thora "Thorite".
Concrete may be cheap when you're making a few rocks, but the material costs add up when it's a structural project. A plywood and epoxy structure will cost the same or less, and will require less labour (although still a lot of work).
The other issue you will come across is the weight of the finished project. Supporting a 1000 pound aquarium is one thing, but another 1000 pounds for the stand and sump might sink your battleship right through the floor.
We had a six ton lathe down on the floor here at one point, so I doubt that weight of any aquarium set up I would create would sink through the floor.
I had not considered the cost of building the frame, and I guess stainless rebar would be expensive.
Sometimes it is interesting to discuss ideas in the forum medium even if they are not the best ideas, because it leads to new ideas and increased knowledge.
I do think that I will stick to welded steel as a means to produce stands,and just buy glass tanks to use a sumps.
On another note,
if you were creating MMLR for a reef tank that had a very strange shape could you use Stainless rebar as a frame to support the weight of the rock? Would the concrete used in the rock have to be different than what has been discussed in this thread? Maybe a layer of the water proof type and then a layer of what has been discussed for porosity?
As far as cost goes I guess it would not make sense, but I am thinking that you could create some interesting shapes and large forms with SS rebar than what could not be created with a PVC frame, or with no frame.
could galvanized steel be used in the same way as stainless steel rebar?
I had not considered the cost of building the frame, and I guess stainless rebar would be expensive.
Sometimes it is interesting to discuss ideas in the forum medium even if they are not the best ideas, because it leads to new ideas and increased knowledge.
I do think that I will stick to welded steel as a means to produce stands,and just buy glass tanks to use a sumps.
On another note,
if you were creating MMLR for a reef tank that had a very strange shape could you use Stainless rebar as a frame to support the weight of the rock? Would the concrete used in the rock have to be different than what has been discussed in this thread? Maybe a layer of the water proof type and then a layer of what has been discussed for porosity?
As far as cost goes I guess it would not make sense, but I am thinking that you could create some interesting shapes and large forms with SS rebar than what could not be created with a PVC frame, or with no frame.
could galvanized steel be used in the same way as stainless steel rebar?
Insane Reefer
New member
Granted, I'm no expert on structural cement, but I think stainless might be a bit much - many bridges, piers, etc. are built in marine environments, using regular rebar - I think the ticket there is that they use cement of the appropriate type that resists the attacks by salt and prevents corrosion of the rebar, i.e. Marine cements, as well as coatings on the rebar itself, i.e. cathodic (zinc) corrosion protection or polymer composite coatings.
Aquariums do usually have a better budget to work with then the states do for structural constructions, and I don't doubt that many do use stainless, but stainless will be used in specific marine applications, not all, by any means.
Maybe if they used stainless rebar for bridges and piers, they would stop collapsing...
This is an interesting technical article on using Microsilica to alter the cement to provide protection for rebar:
http://www.swcc.gov.sa/files\assets...N MICROSILICA ADDED CEMENT IN MARINE ENV.pdf
Aquariums do usually have a better budget to work with then the states do for structural constructions, and I don't doubt that many do use stainless, but stainless will be used in specific marine applications, not all, by any means.
Maybe if they used stainless rebar for bridges and piers, they would stop collapsing...
This is an interesting technical article on using Microsilica to alter the cement to provide protection for rebar:
http://www.swcc.gov.sa/files\assets...N MICROSILICA ADDED CEMENT IN MARINE ENV.pdf
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mr.wilson
.Registered Member
Apart from the structural degradation and chemical reaction between the steel and cement, the issue that faces public aquariums is rust staining. The Sea World near me (Niagara falls) has signs up to inform you that the leaks are normal and will slowly seal themselves with salt.
You can see water dripping through the concrete in many areas, but it seals itself as the salts crystalize. I don't know what effect this has on the cements structural integrity. It may strengthen or weaken it. Nonetheless, the rebar is exposed to corrosive salt water.
A friend of mine rented an industrial unit for his fish warehouse, only to discover that the cement floor had a new metal chip aggregate added to it. After a few months of saltwater spills, his floor turned orange with rust. His landlord ended up moving him to another unit, for fear of structural damage.
Saltwater is pretty tough on cement floors. I've wrecked the floor (serious etching) in a few warehouses over the years. It only takes a year of spills and drips to take the polished surface off of the floor. Once you remove the surface, you get down to larger pores and the cement wears quicker. Epoxy is the only protection.
As far as a steel framework/skeleton goes, I would stick with PVC pipe or rod. It's cheaper, lighter, and just as easy to bend and form, through the use of fittings. You can use a stock PVC sheet to create a stable base.
It's an opportunity for you to combine your art and DIY skills mmm55645.
You can see water dripping through the concrete in many areas, but it seals itself as the salts crystalize. I don't know what effect this has on the cements structural integrity. It may strengthen or weaken it. Nonetheless, the rebar is exposed to corrosive salt water.
A friend of mine rented an industrial unit for his fish warehouse, only to discover that the cement floor had a new metal chip aggregate added to it. After a few months of saltwater spills, his floor turned orange with rust. His landlord ended up moving him to another unit, for fear of structural damage.
Saltwater is pretty tough on cement floors. I've wrecked the floor (serious etching) in a few warehouses over the years. It only takes a year of spills and drips to take the polished surface off of the floor. Once you remove the surface, you get down to larger pores and the cement wears quicker. Epoxy is the only protection.
As far as a steel framework/skeleton goes, I would stick with PVC pipe or rod. It's cheaper, lighter, and just as easy to bend and form, through the use of fittings. You can use a stock PVC sheet to create a stable base.
It's an opportunity for you to combine your art and DIY skills mmm55645.
2004jeepoutlander
New member
Heya Jeff.
Firstly, how long did you allow the rock to air cure before starting the kure? The longer you leave them to hydrate (2 weeks or more?), the shorter the kure period, usually.
Next, how thick are the rocks you made? Rocks thicker than 7 or 8 inches usually take longer to kure.
And lastly, are you using adequate water volume to kure the rock load you have? Needs to be a gallon or two per lbs of rock, changed as soon as the pH hits around 10 or so.
Post this to the thread, if you would, so we can discuss it more with the others input
Thanks for writing,
IR
Firstly, how long did you allow the rock to air cure before starting the kure? The longer you leave them to hydrate (2 weeks or more?), the shorter the kure period, usually.
Next, how thick are the rocks you made? Rocks thicker than 7 or 8 inches usually take longer to kure.
And lastly, are you using adequate water volume to kure the rock load you have? Needs to be a gallon or two per lbs of rock, changed as soon as the pH hits around 10 or so.
Post this to the thread, if you would, so we can discuss it more with the others input
Thanks for writing,
IR
natedogg420
New member
I read this thread from page one and I was just wondering if maybe a person could use large or even small marshmallows to make caves and tunnels in the rock. From what I've heard sugar is not harmful to cement and I would think the marshmallow would just wash out. Just a thought.
ozadars
New member
After drying for two weeks, I put my liverock into the sea. I am hoping to take it back next week if someone doesnt take it out before me. I keep my fingers crossed.
How does "two weeks drying and one week in the sea" sound? I wish I had time for the rock to stay more in the sea but I am moving so I have to take my rock with me.
How does "two weeks drying and one week in the sea" sound? I wish I had time for the rock to stay more in the sea but I am moving so I have to take my rock with me.
Insane Reefer
New member
v6.0
Hey All,
I'm going to post my favorite tips and links every so often so new people can find it all pretty easy. It is a summation of the most commonly asked questions and things I have picked up through making my batches. Some I’ve gleaned from this thread, others I’ve learned from past mistakes and experiments. I've been making DIY man-made rock or aragocrete off and on for close to 8 years. Lately, I have even made some money on my rocks.
This does not contain any information on "Jiffy Rock", the new method I am working on to produce rock in under a week or 10 days. This only pertains to traditionally cured rock methods.
I thought I’d pass this info on â€"œ maybe save someone some frustration or spark a new idea.
I will continue to refine and update this post as more info is added, and repost every so often.
First, good info can be found at these two places - I think everyone who wants to make rock should read these in full. One of the articles gets pretty heavy handed with the science/chemistry aspect, the other babbles on tangents once in a while, but both are worth the read, IMO.
ARAGOCRETE RESEARCH BY TRACY GRAY
Reef Propagation Project:
And this link is for Cement Colorant . They sell it in small amounts in rainbow colors and are very cheap.
List of Appropriate Aggregates
Sand - caribbean/aragonite is “bestâ€Â, but very hard to find at a reasonable price. Any “clean†sand will work â€"œ look for darker grains which could indicate heavy metals. “Toys R Us†carries a play sand that a lot of folks use and report no trouble with. Limestone sand/Pulverized Limestone has gotten good results as a DSB, so should also work and can be found at some Big Box Stores like Home Despot. Sand Blasting sand can also be used and is sugar fine, look for Unimin Brand, or any that says it can be used for filtration â€"œ this will be 99% pure Industrial Quartz. Whatever you choose, keep in mind that the smaller the grain size, the less obvious it is in and on the rock.
Crushed Coral - AKA "CC". Makes nice, realistic rock, but it is expensive.
Crushed Oyster Shell - AKA "OS". Any shell will work, but OS is very cheap at feed stores.
Calcium Carbonate - This stuff comes in a range of textures and grain size â€"œ from sand to gravel like CC. Most feed stores will carry it in some form, and for less then $4/ #50.
Dolomite
â€"œ Same as Calcium Carbonate, just another name (and slight chemical variation) and is just fine to use.
Perlite â€"œ has a pore structure similar to CC, but much, much cheaper â€"œ great for making light weight rock. It is basically inert, puffed glass.
Salt - Many thanks to Travis Stevens for figuring this out! The salt of choice is "Solar Salt Crystals", typically found as a Water Softener Salt. 99% pure salt. Get the coarsest crystals you can find. Solar Cube can be used, but is sort of chunky - makes nice holes though. Boiling the "cubes" rounds off the edges and makes nicer holes. Solar Pellets can also be used, same as Cubes. Look at your grocery stores or wally-worlds if your local hardware doesn't have what you want.
Rock Recipes
Ingredients are measured by volume, not weight!
Travis’ Original Recipe: 4:1 or 3:1 / Salt:Cement
Improved? Recipe: 3:1 or 2:1 / Salt:Cement
Ol' Skool Recipe: 1 to 1.5 : 2 :1 / Cement:CC&OS(mixed â€"œ or use perlite):Sand
Ol' Skool+ Recipe: 1: 1 to 1.5 : 1.5 :1 / Salt:Cement:CC&OS(mixed â€"œ or use perlite):Sand
Mix dry ingredients together first, excepting salt - add tiny amounts of water while vigorously mixing the slurry. Slurry should be “dry†and crumbly, not wet and squishy â€"œ there is a fine line between the two. A wet mix will not have as many natural voids in it, be less porous, and will also bind to the salt, making salt release more difficult. Once you have reached a slightly wetter mix then you think you need, lightly toss the salt into the mixture, and then mix it very quickly â€"œ the more salt that leeches off the crystals, the more deleterious the results can be. Be aware that a dry mix may give the illusion for the first week of being more brittle, but after a week or so, it toughens up and is nice and hard. After you make your rocks, they need to be kept moist and warm for a week or two to achieve the best hydration possible â€"œ though many do take their rock out and start salt release or kuring in 3 days or so, and haven’t reported any bad side effects. However, new info is starting to show that to put your cement in water before the 2 or three week range is needless â€"œ water doesn’t really start doing its job until the hydration is coming to a halt, so leave it sitting and save water and effort. Plastic bags, wet newspaper, wet casting materials and the like will help seal in moisture. If you think the rock might dry too quickly, mist it with a bottle or hose every so often.
Molding Material
Really, pretty much anything that is dry and crumbly/powdery will work. I've even used stuffing bread crumbles, but that draws bugs while it dries.
Soil
Salt
Sand
Clay
A certain portion of the molding material will remain on the rocks - this can usually be removed with a short acid bath, followed by a good scrubbing with a plastic or fine wire, bristle brush.
If you use Rubbermaid or Tupperware, you can reuse molding material over and over again. Line cardboard boxes with plastic to prevent moisture leak and wall collapse.
DO NOT Wet Salt, if it is used as a mold material - this means when working with salt, do not add water to the casting box as you would or might with say clay or sand.
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Now, I will list my tips and tricks, in no particular order. Many will seem stupid or like common sense, but you don’t know about some people’s kids, lol…
Tips and tricks
1. Wear gloves when making rock. If possible, don’t let the cement get on your skin, especially the dry powder. If possible, wear a painter’s mask when measuring and mixing dry cement; this stuff can really burn the inside of your nose.
2. Setup your work area in advance; cover surfaces with plastic or old sheets if needed (like in your kitchen or living room). Fill casting containers with whatever mold material you are using, or have it standing by within easy reach. Give yourself walkways if you are making a lot of rock â€"œ nothing sucks as much as trying to create enough work space after the fact.
3. Think about the weather for not only the day you cast, but the next few days as well, if you plan on doing this outside. Rain can make a mess of things…
4. Use Portland Type I, II (I/II) or III â€"œ these are known to be safe for use and make rock with proper porosity.
5. Mix all aggregates excepting salt into the cement before adding water. Add salt after you have reached the right wet consistency, and mix it in lightly â€"œ the less salt is leeched off the grains of salt, the stronger your final rocks will be. Water softener salt of the type “Solar Salt Crystals†works wonderfully (Thank you Travis Stevens!).
6. I prefer to use crushed coral and sand in my rocks for long term strength, plus salt to add porosity. The aggregates also give realistic details to the rock. My preferred recipe is 1.5 part cement + 1.5 part sand + 1 part crushed coral/shell mix + 1 part salt, but this is expensive to make. You can also use a mix of 1-1.5 cement + 1-2 crushed oyster shells + 1-2 salt.
Mainly, a 1 part cement to 3-4 parts “other†is acceptable, whatever you want to mix together is up to you and you should be ok if you follow the 1:3-4 part rule.
7. Work in layers for added dimension. If you lay a layer of molding stuff in your container, make a few divots in this molding layer first, and add cement to these first to make lumps on the bottom, you can avoid flat bottomed rocks. Now lay the main part of your rock, adding molding material as needed.
8. You can make neat “cliff-face†striations if you take a handful of salt, and lay it just along the top edge of wet cement, forming a narrow line of salt along the edge, laying a thin layer of cement over the salt, and repeating this to form, on the outer edge of your rock, a sort of cliff that looks to be cut by water action.
9. Anything cast thinner than an inch is likely to break, unless you are very careful with it.
10. Find a nice bit of stainless steel or aluminum wire â€"œ 2mm or so in width, and bend a handle for one end (remember you will probably be wearing gloves, so bend accordingly). As you cast your rock, use this wire to poke Lots of little tunnels all through the rock â€"œ all the way through if you can; this will make the rocks extra porous, and give bug life lots of places to hide and propagate in-tank, as well as allowing more water to move through the rock. Alternatively, you can cast the piece, and then poke as much of it as you can â€"œ though this way tends to look a bit contrived. I like the first way better.
11. Once your rock has cured and it has been curing for about a week and if you made it mixed with stuff like crushed coral or shells, mix up a weak acid mix and scrub the outside of your rocks with a stiff bristle brush. Be sure to take proper precautions when working with acid â€"œ not only from burns, but from fumes as well!!! If you only made your rock with salt and cement, ignore the acid wash, as your rocks might dissolve, but still give them a vigorous scrubbing - this will loosen the weakest stuff and get rid of it without shedding it all over your tank. If you have shells or coral, this can make the surface even more porous, and clean cement films from shells and the like that might be on the surface. I use a mixture of 1/2c muriatic acid added to 2c water.
12. You can make “lock together†pieces by wrapping a bit of PVC in something like tissue paper or plastic wrap, sticking it in the wet cement of “part aâ€Â, and then laying plastic wrap over and around the fresh cement/PVC, and then cast “part bâ€Â, making sure to get a good fit around the PVC join. I find this works, but I personally have an easier time if I cast “part a†with PVC set into it, let it cure, then wrap it well with whatever, and cast “part bâ€Â, and I can cast really large pieces this way.
13. “Cement Paintâ€Â. You can make up a slurry of cement and sand, say 1 part cement to 2 or 3 parts sand, made fairly thin and fairly wet and sloppy, and use it to decorate rock with “coralline algaeâ€Â. I use white Portland, but I don’t see why white grout or mortar wouldn’t work as well. You can use cement colorants to color the cement any shade you desire. Working with a paintbrush, you can easily replicate the swirling patterns of coralline. I’ve also used this mix to paint/dry brush grey Portland rocks to white.
14. Branching rock/Coral skeletons. Pick PVC pipe a bit thinner than what you want your final piece to be. Cut into appropriate lengths, cutting one end flat and the other at an angle. Drill plenty of holes in the PVC to help the cement stick on. Drill extra holes on the very end that will allow you to tie the pieces onto the “main branch†with zip ties. You can bend PVC into believable shapes using heat from either a propane torch or a heat gun, and a couple of pairs of pliers (use appropriate precautions). After you have your PVC framework, mix a thicker blend of Cement Paint (less water, more cement) and paint/dip the skeleton, covering completely. I recommend hanging to dry, and dipping several times, using a paintbrush to smooth it out and prevent weird drips. When done coating, tie a grocery bag around the hanging piece to preserve moisture and allow to cure 48 hours or more.
15. Think about how corals come to you, as frags and whole colonies, and think about how hard it can be to attach these in your typical rock pile. Flatter surfaces and shallow bowls in larger rock shapes can make latter placement easier.
16. You can make rock “shells†if you want to avoid the rock pile look altogether and these are only limited to your imagination and size constraints. You can stuff the cavity in the back of this hollow construction with cheap $1.99/lbs rock, or whatever you want. I DO NOT recommend making these with the cement and salt only recipe! Make a form of some sort (use your imagination), put it in a box that will fit into your tank (making a rock too big for the target tank blows), and secure it to one side, or more (for multi-part casts) with duct tape. Line the rest of the box with plastic. I made my form from plastic grocery bags stuffed into a garbage bag, with a little air added, and taped that into the target box. Slowly build the shell wall (adding details as you wish), filling the box with salt/molding material, until you have the form covered with a fairly uniform covering of cement. LEAVE ALONE FOR A WEEK! Cover with plastic if you can. See my gallery for pictures of the “â€ÂReef Face†or “Nessyâ€Â.
17. Frag Plugs. If you have extra cement at the end of the day, make frag plugs by using a mini muffin pan, and filling with ½in. of cement. Spray the pan with cooking spray for easier release. These can be put in a mesh bag and cured in the toilet tank.
18. Hate scraping the back wall of your tank? You can make thin, wall covering sheets, that can be glued with silicone to the back wall of your tank. Alternatively you could make shelves along those lines. I find casting on a sheet of glass covered in plastic works best for this. Also marking out the actual measurements of the back wall onto the glass helps to avoid sizing issues. I DO NOT recommend using the salt and cement only recipes for this application, nor the use of any salt at all! I also mix this just a little wetter than I normally use. Once you are setup, just drool the cement onto the covered glass. I tried doing large sheets, but these mostly were too weak to hold up and heavy. I find making smaller pieces (12inX12in or so) that abut like a puzzle work best, and sort of give the illusion of looking at a cracked and crevassed reef wall. After you cast these, they need to be kept moist and unmoved for 3 days, 7 days being much better. Believe me. They do. And you will need to mist them once a day. I just covered mine with a garbage bag and used a water bottle to mist it. I recommend an acid wash, as described above, once these have kured for a week.
19. If you make a rock or rocks you don't like, either use fresh cement mix to add some new bits, or break the rock up and use it as aggregate in your next batch - no waste is good.
20. The moister you can keep the cement while it cures, the harder the final rock will be - try wrapping it in a bag, or misting it while it cures. Supposedly, if you can let it sit for two to four weeks before starting to water kure, it will dramatically speed the kure time.
21. Dust your molding sand with oat flour for easy removal of surface sand. Thanks Rhody!
22. Mix molasses with your molding sand to give it more texture. Thanks Rhody!
Various things I have used and have worked for me for adding details:
1. Cemented Nylon String. Makes realistic tube worm/duster tubes. Make a thin paste of just cement, and dip small lengths of the sting in. Wipe excess off between fingers and lay onto the rock in desired figure.
2. Veggie Capsules. These can make little tunnels when laid end to end in the wet cement, and then covered with more cement. Or poke into outside edges to mimic polyp holes. Do NOT mix into the cement mix.
3. Nori Sheets. These can be wetted and formed into shapes or rolled into tunnels.
4. Balloons. Both the round and “animal†ones work. I find that filling them with water makes them stronger. Doubling them up works well too. Make sure that you can get the balloon out afterward - i.e. leave the knot sticking out.
5. Cardboard Rolls. Can be cut to form bracing, tunnels or for pillar shapes. Be sure to use it in such a way as will allow you to remove it after a few days of kuring. Hemostats work great for grabbing a-hold and pulling it out.
6. Tissue Paper. The white stuff you find in gift bags. Disintegrates quickly during kure. You can make little (or big) “salt bagsâ€Â, that you can lay into the middle of larger rocks to give more holes for ‘pods and the like. Can be used to make caves and tunnels. Just use a small bit of paper, lay some salt in it and twist or tuck the ends â€"œ a small bit of cotton thread could be used to secure the package too.
7. Pasta. Must be cooked “Al Dente†before use. Do not mix into cement, it only makes a mess and is a pain to get out of the rock as it gets really hard and crunchy when the rock dries (ever scraped 3 day old pasta off a plate?).
Kured Rock that the pasta is stuck in...
Use to add spaces in the rock, or tunnels with spaghetti (at your own risk). Rigatoni adds a nice effect if placed just right. If you use pasta, you MUST keep the rock moist at all times â€"œ if the pasta dries, it will most likely never come out, ever.
8. Jelly. No, not like PB&J, but those toys, etc made of the product known as silicone jelly â€"œ often comes in wiggly balls. Also fishing bait worms made of the jelly/rubber. No need to lube them â€"œ they will release just fine.
Things that DO NOT work:
1. Vinegar/acid kuring. Does have its uses, but don’t expect it to kure your rock â€"œ it won’t.
2. Bio-degradable packing peanuts/Cheesy-poofs. I can find no way to really use these that is also safe for the tank.
3. Fish food pellets. That was really, really nasty. I don’t want to go there.
4. Uncooked Pasta. As pasta absorbs water, it expands, causing the cement to fracture and crack â€"œ cook it al dente if you really want to use it.
5. Alka-Seltzer . Doesn’t work. It dissolves too quickly.
6. Yeast. Doesn't work. pH kills the cells before they can respirate. Though during the Kure, this might be a speed option.
7. Co2. Ok â€"œ it does work, but only under high pressure. Adding into H2O will only make soda pop (carbonic acid), and eat away at your rock, causing fresh, high pH surfaces to be revealed.
Salt Release
If you used salt in your rock, it must be removed before kuring can happen. Salt will release in hot water much easier than it will in cold water, and boiling water works best of all. It generally takes two days to two weeks to remove salt, based on factors such as wetness of the slurry, aggregates used and density of the cast piece. Removing the salt will take several water changes. Boiling is also a viable option, and may also help reduce pH - hydrogen carbonate ions can decompose forming insoluble calcium (or magnesium) carbonate, which then are flushed away.
If you aren’t sure that the salt is gone, you can do a “Taste Testâ€Â. After draining and rinsing the rock (pick your largest/thickest piece), allow the water to drain out for a few minutes. Pick the rock up and use your finger to catch a drip of water from the bottom of the rock and taste it. If there is still salt present, the water drop will be salty. If the salt is gone, the drop will taste of mineral water and very slightly sweet.
Rock Kuring
Kuring your rock is the next hurdle. It is really, really best to leave your rock alone for at least a week before starting this step. According to Quikcrete reps, it takes 7-14 days for the rock to stop curing/hardening (though this process is actually going on for a lot, lot longer) - even though it looks and feels done. Testing standards say it takes 28 days to reach full strength and before testing for commercial applications can commence. By putting your rock in the kure bin too soon, you are wasting a lot of water, prolonging the hydration process and making weaker rock. Rocks during this 2-4 week period will naturally loose pH - from 12-13 at casting time down to 9-10, with NO WATER USED. I theorize that rock left longer, like 5 weeks, will only need a week or so of kure time (and a lot less water and effort!).
Kuring is pretty straight forward. Lots of time, and lots of water changes with adequate water volume, unless you have access to a reasonably clean waterway. This step is dramatically decreased if you wait until the 4-5 week range of your rocks life. Powerheads help force water through the rock and help the insides kure out. Adding heat to the bucket, upwards of 90°F will speed things along.
When your bucket kured rock quits leeching out white scum on the surface of the water, and stops leaving a white residue on the bottom of the bucket and on the rocks themselves, you can start checking for pH. Rock has been known to kure in as little as 2 weeks, but most bucket/bin kured rock takes 6-8 weeks to reach safe levels â€"œ some will take up to 3 months. Be prepared to wait.
To properly test for pH, change the water â€"œ use saltwater â€"œ saltwater is preferred since this is what the rock will be sitting in for the rest of its life. Feel free to use old water from a tank change, just test the pH prior to use. Let the rock sit in this for 3-4 days without air or powerheads â€"œ you want still, stagnant water for this. After the 3-4 days, give the water a bit of a stirring and check pH with appropriate test kit. If it is in the acceptable range of 8.0 to 8.6, it is probably safe to use. If not, continue to kure.
You can use any acceptable pH testing method. The test you use should have a testing range of 5-10 at a minimum. I like using Litmus Paper. It can read pH from 1-14, and is fairly easy to read. Litmus paper can be gotten at “Hobby Lobby†for $3.89 per 100 strips. These can also be used to test your reefs’ pH
Litmus can also be found at pharmacies, online, and at other full service hobby stores, usually in the section that has things like “Magic Crystalsâ€Â, and horseshoe/bar magnets â€"œ the “Science Sectionâ€Â.
Once kuring has finished - reads between 7 and 8.6 on pH, your rock can be used
If added to a newly established tank, you can go ahead and put it all in at once. If the tank is older, with inhabitants, you may wish to add a rock or two at a time, to allow the system to “settle†between each addition. Maintain pH testing for the first two weeks and buffer if needed.
Expect an algae bloom. :eek1:
A few people, those who either have waterways to kure in, or those with really butch systems have reported no algae blooms, but I suspect they are the exception, not the rule. If your tank blooms, don’t panic. Most tanks bloom within the maturation period anyway. Double check your system for things like NO2 and NO3, and other algae causing symptoms and correct anything that isn’t up to snuff. Take all the normal steps to curtail the growth, but then just ride it out. If the bloom is caused by the rocks, the algae will soon deplete the readily available nutrients and starve itself out. If it doesn’t go away within a few months, then you should check into other reasons for the bloom.
New Tip! If you place your rock in tank with low light for two weeks to a month, you can avoid most of the bright green covering algae â€"œ low lights allow the rock to settle in without being attacked by algae so badly…
And lastly, I'd like to take a minute to share some thoughts on Crumbly Rock. This is mainly for the Noobs, who haven't made very much, or those who have been disappointed in the rock they have made. Anyone else who wants to add their thoughts are more than welcome to.
Hey All,
I'm going to post my favorite tips and links every so often so new people can find it all pretty easy. It is a summation of the most commonly asked questions and things I have picked up through making my batches. Some I’ve gleaned from this thread, others I’ve learned from past mistakes and experiments. I've been making DIY man-made rock or aragocrete off and on for close to 8 years. Lately, I have even made some money on my rocks.
This does not contain any information on "Jiffy Rock", the new method I am working on to produce rock in under a week or 10 days. This only pertains to traditionally cured rock methods.
I thought I’d pass this info on â€"œ maybe save someone some frustration or spark a new idea.
I will continue to refine and update this post as more info is added, and repost every so often.
First, good info can be found at these two places - I think everyone who wants to make rock should read these in full. One of the articles gets pretty heavy handed with the science/chemistry aspect, the other babbles on tangents once in a while, but both are worth the read, IMO.
ARAGOCRETE RESEARCH BY TRACY GRAY
Reef Propagation Project:
And this link is for Cement Colorant . They sell it in small amounts in rainbow colors and are very cheap.
List of Appropriate Aggregates
Sand - caribbean/aragonite is “bestâ€Â, but very hard to find at a reasonable price. Any “clean†sand will work â€"œ look for darker grains which could indicate heavy metals. “Toys R Us†carries a play sand that a lot of folks use and report no trouble with. Limestone sand/Pulverized Limestone has gotten good results as a DSB, so should also work and can be found at some Big Box Stores like Home Despot. Sand Blasting sand can also be used and is sugar fine, look for Unimin Brand, or any that says it can be used for filtration â€"œ this will be 99% pure Industrial Quartz. Whatever you choose, keep in mind that the smaller the grain size, the less obvious it is in and on the rock.
Crushed Coral - AKA "CC". Makes nice, realistic rock, but it is expensive.
Crushed Oyster Shell - AKA "OS". Any shell will work, but OS is very cheap at feed stores.
Calcium Carbonate - This stuff comes in a range of textures and grain size â€"œ from sand to gravel like CC. Most feed stores will carry it in some form, and for less then $4/ #50.
Dolomite
â€"œ Same as Calcium Carbonate, just another name (and slight chemical variation) and is just fine to use.Perlite â€"œ has a pore structure similar to CC, but much, much cheaper â€"œ great for making light weight rock. It is basically inert, puffed glass.
Salt - Many thanks to Travis Stevens for figuring this out! The salt of choice is "Solar Salt Crystals", typically found as a Water Softener Salt. 99% pure salt. Get the coarsest crystals you can find. Solar Cube can be used, but is sort of chunky - makes nice holes though. Boiling the "cubes" rounds off the edges and makes nicer holes. Solar Pellets can also be used, same as Cubes. Look at your grocery stores or wally-worlds if your local hardware doesn't have what you want.
Rock Recipes
Ingredients are measured by volume, not weight!
Travis’ Original Recipe: 4:1 or 3:1 / Salt:Cement
Improved? Recipe: 3:1 or 2:1 / Salt:Cement
Ol' Skool Recipe: 1 to 1.5 : 2 :1 / Cement:CC&OS(mixed â€"œ or use perlite):Sand
Ol' Skool+ Recipe: 1: 1 to 1.5 : 1.5 :1 / Salt:Cement:CC&OS(mixed â€"œ or use perlite):Sand
Mix dry ingredients together first, excepting salt - add tiny amounts of water while vigorously mixing the slurry. Slurry should be “dry†and crumbly, not wet and squishy â€"œ there is a fine line between the two. A wet mix will not have as many natural voids in it, be less porous, and will also bind to the salt, making salt release more difficult. Once you have reached a slightly wetter mix then you think you need, lightly toss the salt into the mixture, and then mix it very quickly â€"œ the more salt that leeches off the crystals, the more deleterious the results can be. Be aware that a dry mix may give the illusion for the first week of being more brittle, but after a week or so, it toughens up and is nice and hard. After you make your rocks, they need to be kept moist and warm for a week or two to achieve the best hydration possible â€"œ though many do take their rock out and start salt release or kuring in 3 days or so, and haven’t reported any bad side effects. However, new info is starting to show that to put your cement in water before the 2 or three week range is needless â€"œ water doesn’t really start doing its job until the hydration is coming to a halt, so leave it sitting and save water and effort. Plastic bags, wet newspaper, wet casting materials and the like will help seal in moisture. If you think the rock might dry too quickly, mist it with a bottle or hose every so often.
Molding Material
Really, pretty much anything that is dry and crumbly/powdery will work. I've even used stuffing bread crumbles, but that draws bugs while it dries.
Soil
Salt
Sand
Clay
A certain portion of the molding material will remain on the rocks - this can usually be removed with a short acid bath, followed by a good scrubbing with a plastic or fine wire, bristle brush.
If you use Rubbermaid or Tupperware, you can reuse molding material over and over again. Line cardboard boxes with plastic to prevent moisture leak and wall collapse.
DO NOT Wet Salt, if it is used as a mold material - this means when working with salt, do not add water to the casting box as you would or might with say clay or sand.
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Now, I will list my tips and tricks, in no particular order. Many will seem stupid or like common sense, but you don’t know about some people’s kids, lol…
Tips and tricks
1. Wear gloves when making rock. If possible, don’t let the cement get on your skin, especially the dry powder. If possible, wear a painter’s mask when measuring and mixing dry cement; this stuff can really burn the inside of your nose.
2. Setup your work area in advance; cover surfaces with plastic or old sheets if needed (like in your kitchen or living room). Fill casting containers with whatever mold material you are using, or have it standing by within easy reach. Give yourself walkways if you are making a lot of rock â€"œ nothing sucks as much as trying to create enough work space after the fact.
3. Think about the weather for not only the day you cast, but the next few days as well, if you plan on doing this outside. Rain can make a mess of things…
4. Use Portland Type I, II (I/II) or III â€"œ these are known to be safe for use and make rock with proper porosity.
5. Mix all aggregates excepting salt into the cement before adding water. Add salt after you have reached the right wet consistency, and mix it in lightly â€"œ the less salt is leeched off the grains of salt, the stronger your final rocks will be. Water softener salt of the type “Solar Salt Crystals†works wonderfully (Thank you Travis Stevens!).
6. I prefer to use crushed coral and sand in my rocks for long term strength, plus salt to add porosity. The aggregates also give realistic details to the rock. My preferred recipe is 1.5 part cement + 1.5 part sand + 1 part crushed coral/shell mix + 1 part salt, but this is expensive to make. You can also use a mix of 1-1.5 cement + 1-2 crushed oyster shells + 1-2 salt.
Mainly, a 1 part cement to 3-4 parts “other†is acceptable, whatever you want to mix together is up to you and you should be ok if you follow the 1:3-4 part rule.
7. Work in layers for added dimension. If you lay a layer of molding stuff in your container, make a few divots in this molding layer first, and add cement to these first to make lumps on the bottom, you can avoid flat bottomed rocks. Now lay the main part of your rock, adding molding material as needed.
8. You can make neat “cliff-face†striations if you take a handful of salt, and lay it just along the top edge of wet cement, forming a narrow line of salt along the edge, laying a thin layer of cement over the salt, and repeating this to form, on the outer edge of your rock, a sort of cliff that looks to be cut by water action.
9. Anything cast thinner than an inch is likely to break, unless you are very careful with it.
10. Find a nice bit of stainless steel or aluminum wire â€"œ 2mm or so in width, and bend a handle for one end (remember you will probably be wearing gloves, so bend accordingly). As you cast your rock, use this wire to poke Lots of little tunnels all through the rock â€"œ all the way through if you can; this will make the rocks extra porous, and give bug life lots of places to hide and propagate in-tank, as well as allowing more water to move through the rock. Alternatively, you can cast the piece, and then poke as much of it as you can â€"œ though this way tends to look a bit contrived. I like the first way better.
11. Once your rock has cured and it has been curing for about a week and if you made it mixed with stuff like crushed coral or shells, mix up a weak acid mix and scrub the outside of your rocks with a stiff bristle brush. Be sure to take proper precautions when working with acid â€"œ not only from burns, but from fumes as well!!! If you only made your rock with salt and cement, ignore the acid wash, as your rocks might dissolve, but still give them a vigorous scrubbing - this will loosen the weakest stuff and get rid of it without shedding it all over your tank. If you have shells or coral, this can make the surface even more porous, and clean cement films from shells and the like that might be on the surface. I use a mixture of 1/2c muriatic acid added to 2c water.
12. You can make “lock together†pieces by wrapping a bit of PVC in something like tissue paper or plastic wrap, sticking it in the wet cement of “part aâ€Â, and then laying plastic wrap over and around the fresh cement/PVC, and then cast “part bâ€Â, making sure to get a good fit around the PVC join. I find this works, but I personally have an easier time if I cast “part a†with PVC set into it, let it cure, then wrap it well with whatever, and cast “part bâ€Â, and I can cast really large pieces this way.
13. “Cement Paintâ€Â. You can make up a slurry of cement and sand, say 1 part cement to 2 or 3 parts sand, made fairly thin and fairly wet and sloppy, and use it to decorate rock with “coralline algaeâ€Â. I use white Portland, but I don’t see why white grout or mortar wouldn’t work as well. You can use cement colorants to color the cement any shade you desire. Working with a paintbrush, you can easily replicate the swirling patterns of coralline. I’ve also used this mix to paint/dry brush grey Portland rocks to white.
14. Branching rock/Coral skeletons. Pick PVC pipe a bit thinner than what you want your final piece to be. Cut into appropriate lengths, cutting one end flat and the other at an angle. Drill plenty of holes in the PVC to help the cement stick on. Drill extra holes on the very end that will allow you to tie the pieces onto the “main branch†with zip ties. You can bend PVC into believable shapes using heat from either a propane torch or a heat gun, and a couple of pairs of pliers (use appropriate precautions). After you have your PVC framework, mix a thicker blend of Cement Paint (less water, more cement) and paint/dip the skeleton, covering completely. I recommend hanging to dry, and dipping several times, using a paintbrush to smooth it out and prevent weird drips. When done coating, tie a grocery bag around the hanging piece to preserve moisture and allow to cure 48 hours or more.
15. Think about how corals come to you, as frags and whole colonies, and think about how hard it can be to attach these in your typical rock pile. Flatter surfaces and shallow bowls in larger rock shapes can make latter placement easier.
16. You can make rock “shells†if you want to avoid the rock pile look altogether and these are only limited to your imagination and size constraints. You can stuff the cavity in the back of this hollow construction with cheap $1.99/lbs rock, or whatever you want. I DO NOT recommend making these with the cement and salt only recipe! Make a form of some sort (use your imagination), put it in a box that will fit into your tank (making a rock too big for the target tank blows), and secure it to one side, or more (for multi-part casts) with duct tape. Line the rest of the box with plastic. I made my form from plastic grocery bags stuffed into a garbage bag, with a little air added, and taped that into the target box. Slowly build the shell wall (adding details as you wish), filling the box with salt/molding material, until you have the form covered with a fairly uniform covering of cement. LEAVE ALONE FOR A WEEK! Cover with plastic if you can. See my gallery for pictures of the “â€ÂReef Face†or “Nessyâ€Â.
17. Frag Plugs. If you have extra cement at the end of the day, make frag plugs by using a mini muffin pan, and filling with ½in. of cement. Spray the pan with cooking spray for easier release. These can be put in a mesh bag and cured in the toilet tank.
18. Hate scraping the back wall of your tank? You can make thin, wall covering sheets, that can be glued with silicone to the back wall of your tank. Alternatively you could make shelves along those lines. I find casting on a sheet of glass covered in plastic works best for this. Also marking out the actual measurements of the back wall onto the glass helps to avoid sizing issues. I DO NOT recommend using the salt and cement only recipes for this application, nor the use of any salt at all! I also mix this just a little wetter than I normally use. Once you are setup, just drool the cement onto the covered glass. I tried doing large sheets, but these mostly were too weak to hold up and heavy. I find making smaller pieces (12inX12in or so) that abut like a puzzle work best, and sort of give the illusion of looking at a cracked and crevassed reef wall. After you cast these, they need to be kept moist and unmoved for 3 days, 7 days being much better. Believe me. They do. And you will need to mist them once a day. I just covered mine with a garbage bag and used a water bottle to mist it. I recommend an acid wash, as described above, once these have kured for a week.
19. If you make a rock or rocks you don't like, either use fresh cement mix to add some new bits, or break the rock up and use it as aggregate in your next batch - no waste is good.
20. The moister you can keep the cement while it cures, the harder the final rock will be - try wrapping it in a bag, or misting it while it cures. Supposedly, if you can let it sit for two to four weeks before starting to water kure, it will dramatically speed the kure time.
21. Dust your molding sand with oat flour for easy removal of surface sand. Thanks Rhody!
22. Mix molasses with your molding sand to give it more texture. Thanks Rhody!
Various things I have used and have worked for me for adding details:
1. Cemented Nylon String. Makes realistic tube worm/duster tubes. Make a thin paste of just cement, and dip small lengths of the sting in. Wipe excess off between fingers and lay onto the rock in desired figure.
2. Veggie Capsules. These can make little tunnels when laid end to end in the wet cement, and then covered with more cement. Or poke into outside edges to mimic polyp holes. Do NOT mix into the cement mix.
3. Nori Sheets. These can be wetted and formed into shapes or rolled into tunnels.
4. Balloons. Both the round and “animal†ones work. I find that filling them with water makes them stronger. Doubling them up works well too. Make sure that you can get the balloon out afterward - i.e. leave the knot sticking out.
5. Cardboard Rolls. Can be cut to form bracing, tunnels or for pillar shapes. Be sure to use it in such a way as will allow you to remove it after a few days of kuring. Hemostats work great for grabbing a-hold and pulling it out.
6. Tissue Paper. The white stuff you find in gift bags. Disintegrates quickly during kure. You can make little (or big) “salt bagsâ€Â, that you can lay into the middle of larger rocks to give more holes for ‘pods and the like. Can be used to make caves and tunnels. Just use a small bit of paper, lay some salt in it and twist or tuck the ends â€"œ a small bit of cotton thread could be used to secure the package too.
7. Pasta. Must be cooked “Al Dente†before use. Do not mix into cement, it only makes a mess and is a pain to get out of the rock as it gets really hard and crunchy when the rock dries (ever scraped 3 day old pasta off a plate?).
Kured Rock that the pasta is stuck in...
Use to add spaces in the rock, or tunnels with spaghetti (at your own risk). Rigatoni adds a nice effect if placed just right. If you use pasta, you MUST keep the rock moist at all times â€"œ if the pasta dries, it will most likely never come out, ever.
8. Jelly. No, not like PB&J, but those toys, etc made of the product known as silicone jelly â€"œ often comes in wiggly balls. Also fishing bait worms made of the jelly/rubber. No need to lube them â€"œ they will release just fine.
Things that DO NOT work:
1. Vinegar/acid kuring. Does have its uses, but don’t expect it to kure your rock â€"œ it won’t.
2. Bio-degradable packing peanuts/Cheesy-poofs. I can find no way to really use these that is also safe for the tank.
3. Fish food pellets. That was really, really nasty. I don’t want to go there.
4. Uncooked Pasta. As pasta absorbs water, it expands, causing the cement to fracture and crack â€"œ cook it al dente if you really want to use it.
5. Alka-Seltzer . Doesn’t work. It dissolves too quickly.
6. Yeast. Doesn't work. pH kills the cells before they can respirate. Though during the Kure, this might be a speed option.
7. Co2. Ok â€"œ it does work, but only under high pressure. Adding into H2O will only make soda pop (carbonic acid), and eat away at your rock, causing fresh, high pH surfaces to be revealed.
Salt Release
If you used salt in your rock, it must be removed before kuring can happen. Salt will release in hot water much easier than it will in cold water, and boiling water works best of all. It generally takes two days to two weeks to remove salt, based on factors such as wetness of the slurry, aggregates used and density of the cast piece. Removing the salt will take several water changes. Boiling is also a viable option, and may also help reduce pH - hydrogen carbonate ions can decompose forming insoluble calcium (or magnesium) carbonate, which then are flushed away.
If you aren’t sure that the salt is gone, you can do a “Taste Testâ€Â. After draining and rinsing the rock (pick your largest/thickest piece), allow the water to drain out for a few minutes. Pick the rock up and use your finger to catch a drip of water from the bottom of the rock and taste it. If there is still salt present, the water drop will be salty. If the salt is gone, the drop will taste of mineral water and very slightly sweet.
Rock Kuring
Kuring your rock is the next hurdle. It is really, really best to leave your rock alone for at least a week before starting this step. According to Quikcrete reps, it takes 7-14 days for the rock to stop curing/hardening (though this process is actually going on for a lot, lot longer) - even though it looks and feels done. Testing standards say it takes 28 days to reach full strength and before testing for commercial applications can commence. By putting your rock in the kure bin too soon, you are wasting a lot of water, prolonging the hydration process and making weaker rock. Rocks during this 2-4 week period will naturally loose pH - from 12-13 at casting time down to 9-10, with NO WATER USED. I theorize that rock left longer, like 5 weeks, will only need a week or so of kure time (and a lot less water and effort!).
Kuring is pretty straight forward. Lots of time, and lots of water changes with adequate water volume, unless you have access to a reasonably clean waterway. This step is dramatically decreased if you wait until the 4-5 week range of your rocks life. Powerheads help force water through the rock and help the insides kure out. Adding heat to the bucket, upwards of 90°F will speed things along.
When your bucket kured rock quits leeching out white scum on the surface of the water, and stops leaving a white residue on the bottom of the bucket and on the rocks themselves, you can start checking for pH. Rock has been known to kure in as little as 2 weeks, but most bucket/bin kured rock takes 6-8 weeks to reach safe levels â€"œ some will take up to 3 months. Be prepared to wait.
To properly test for pH, change the water â€"œ use saltwater â€"œ saltwater is preferred since this is what the rock will be sitting in for the rest of its life. Feel free to use old water from a tank change, just test the pH prior to use. Let the rock sit in this for 3-4 days without air or powerheads â€"œ you want still, stagnant water for this. After the 3-4 days, give the water a bit of a stirring and check pH with appropriate test kit. If it is in the acceptable range of 8.0 to 8.6, it is probably safe to use. If not, continue to kure.
You can use any acceptable pH testing method. The test you use should have a testing range of 5-10 at a minimum. I like using Litmus Paper. It can read pH from 1-14, and is fairly easy to read. Litmus paper can be gotten at “Hobby Lobby†for $3.89 per 100 strips. These can also be used to test your reefs’ pH
Litmus can also be found at pharmacies, online, and at other full service hobby stores, usually in the section that has things like “Magic Crystalsâ€Â, and horseshoe/bar magnets â€"œ the “Science Sectionâ€Â.Once kuring has finished - reads between 7 and 8.6 on pH, your rock can be used
If added to a newly established tank, you can go ahead and put it all in at once. If the tank is older, with inhabitants, you may wish to add a rock or two at a time, to allow the system to “settle†between each addition. Maintain pH testing for the first two weeks and buffer if needed.
Expect an algae bloom. :eek1:
A few people, those who either have waterways to kure in, or those with really butch systems have reported no algae blooms, but I suspect they are the exception, not the rule. If your tank blooms, don’t panic. Most tanks bloom within the maturation period anyway. Double check your system for things like NO2 and NO3, and other algae causing symptoms and correct anything that isn’t up to snuff. Take all the normal steps to curtail the growth, but then just ride it out. If the bloom is caused by the rocks, the algae will soon deplete the readily available nutrients and starve itself out. If it doesn’t go away within a few months, then you should check into other reasons for the bloom.
New Tip! If you place your rock in tank with low light for two weeks to a month, you can avoid most of the bright green covering algae â€"œ low lights allow the rock to settle in without being attacked by algae so badly…
And lastly, I'd like to take a minute to share some thoughts on Crumbly Rock. This is mainly for the Noobs, who haven't made very much, or those who have been disappointed in the rock they have made. Anyone else who wants to add their thoughts are more than welcome to.
Insane Reefer
New member
In conclusion, I'd like to address "Expectations". I have a feeling that some people are expecting the rocks they make to be as hard as cement blocks or cement stepping stone, because, after all, they are made with cement, so it should be, right? Well, in this case, no - they won't be.
Let's compare our slurry to a typical cement pour slurry.
First, poured slurry's are made with a higher ratio of cement then we usually use. Next, they add enough water that they can pour the slurry - much like an ice cream slurry. I've never been able to pour my slurry; we try to make ours as dry as we can and still have it stick together. Then take a look at the aggregates - they use silica sands and gravel, we usually use calcium based substances when we can - there is a marked difference in each of these as far as strength goes.
And finally, when cement is poured, they try to get it settled down - they drag tools over it to smooth it and make sure it is even and all that. We go for as much openness as possible, and we try not to pack the slurry if we can help it.
Looking at it like this might help people come to a better understanding of what a reasonable expectation of their rock might be.
Our rock is going to flake and shed. The more porous the rock is, the more likely it will be to do so. The better the slurry is made though, the less you will see of it. Maybe you have seen a box of real live rock just after shipping. If you have, you probably noticed the rubble in the bottom. Most distributors are not in the habit of making up the extra weight in a box with rubble - that would be bad business. Most of that rubble simply came from the rock during shipping. Calcium based rock is not the strongest in the world, and essentially, our rock is calcium based.
But flaking and shedding are not the same as brittle rock. Your rock is brittle if you can snap large pieces off after a month or two. Small bits rubbing off is not necessarily indicative of failed rock, those could just be pieces that didn't get adhered well.
My first piece of advice would be to wait. It takes a month for the curing process to reach near completion and the rock to reach something close to its final strength. If your rock seems brittle or flaky, beyond what you should reasonably expect, just leave it alone for a month, in a moist (not wet), warm environment, like a plastic bag. Some of the early salt rock I made seemed really brittle, too brittle to use, certainly, for the first couple of weeks. It was when I later found it again, in the bottom of a bucket outside, that I realized how nicely it had hardened up. If after leaving it alone, you can easily snap sizable portions off (golf ball sized?), then you have a problem.
My next pieces of advice would be to use a stiff bristled brush, like what you use to clean your grill, to give your rock a good once over when it reaches about four weeks old (or after the pH test in Jiffy Rock). This will remove about 90% of the shedding and flaking, if your shedding and flaking isn't due to rock failure that is. If you have done this and a couple of weeks later it is readily shedding, then I'd say you might have a problem.
Remember that even slight variations can make a huge difference. Humidity and Temperature at casting and during the cure can make drastic differences. A tablespoon of water can make a difference on smaller batches - too wet and too dry can be a fine line. Differences in the cement itself can wildly vary - every plant uses its own recipe to make the clinker. Differences in local materials used for the recipe can ofter vary with availability and cost. My white cement is going to be different then Neptunes' cement, and his, even from the same plant as Sunkools' may vary as well, from lot to lot.
Salt can mess up the strength of your rock, so if you used salt, think about that. If you added it upfront, with the aggregates, you may have over-mixed it and too much salt mixed into the batch. Try adding the salt after the slurry is mixed and ready - and just lightly mix it in.
A ratio of 1:3 or 1:4 is best for us. 1 part cement to 3-4 parts "other", which includes salt.
If you are trying Jiffy Rocks, do not remove the salt prior to baking.
And finally, realize that even the best made rock can still chip and shed once in a while. Moving it around in your tank, bumping it against each other (esp larger pieces), will inevitably cause bits to shed or chip off, unless you went for rounded ball like shapes, which seem to loose less, but also seem less porous and less attractive too.
I hope this helps a few people out there. I know that having something you worked hard on, that doesn't turn out like you wanted, can be disappointing. Hopefully this will help people understand what they should expect, and what they can do to correct it...
Well, I think that about covers my repertoire. I apologize for the length of this post, but hopefully some of you will find something of use…
I encourage the rest of you to take some time to write up your experiences and tips and share them with us â€"œ by sharing our experiences, we all learn and get better and better at making our own rock.
Good Luck, and Rock On!
:rollface:
Let's compare our slurry to a typical cement pour slurry.
First, poured slurry's are made with a higher ratio of cement then we usually use. Next, they add enough water that they can pour the slurry - much like an ice cream slurry. I've never been able to pour my slurry; we try to make ours as dry as we can and still have it stick together. Then take a look at the aggregates - they use silica sands and gravel, we usually use calcium based substances when we can - there is a marked difference in each of these as far as strength goes.
And finally, when cement is poured, they try to get it settled down - they drag tools over it to smooth it and make sure it is even and all that. We go for as much openness as possible, and we try not to pack the slurry if we can help it.
Looking at it like this might help people come to a better understanding of what a reasonable expectation of their rock might be.
Our rock is going to flake and shed. The more porous the rock is, the more likely it will be to do so. The better the slurry is made though, the less you will see of it. Maybe you have seen a box of real live rock just after shipping. If you have, you probably noticed the rubble in the bottom. Most distributors are not in the habit of making up the extra weight in a box with rubble - that would be bad business. Most of that rubble simply came from the rock during shipping. Calcium based rock is not the strongest in the world, and essentially, our rock is calcium based.
But flaking and shedding are not the same as brittle rock. Your rock is brittle if you can snap large pieces off after a month or two. Small bits rubbing off is not necessarily indicative of failed rock, those could just be pieces that didn't get adhered well.
My first piece of advice would be to wait. It takes a month for the curing process to reach near completion and the rock to reach something close to its final strength. If your rock seems brittle or flaky, beyond what you should reasonably expect, just leave it alone for a month, in a moist (not wet), warm environment, like a plastic bag. Some of the early salt rock I made seemed really brittle, too brittle to use, certainly, for the first couple of weeks. It was when I later found it again, in the bottom of a bucket outside, that I realized how nicely it had hardened up. If after leaving it alone, you can easily snap sizable portions off (golf ball sized?), then you have a problem.
My next pieces of advice would be to use a stiff bristled brush, like what you use to clean your grill, to give your rock a good once over when it reaches about four weeks old (or after the pH test in Jiffy Rock). This will remove about 90% of the shedding and flaking, if your shedding and flaking isn't due to rock failure that is. If you have done this and a couple of weeks later it is readily shedding, then I'd say you might have a problem.
Remember that even slight variations can make a huge difference. Humidity and Temperature at casting and during the cure can make drastic differences. A tablespoon of water can make a difference on smaller batches - too wet and too dry can be a fine line. Differences in the cement itself can wildly vary - every plant uses its own recipe to make the clinker. Differences in local materials used for the recipe can ofter vary with availability and cost. My white cement is going to be different then Neptunes' cement, and his, even from the same plant as Sunkools' may vary as well, from lot to lot.
Salt can mess up the strength of your rock, so if you used salt, think about that. If you added it upfront, with the aggregates, you may have over-mixed it and too much salt mixed into the batch. Try adding the salt after the slurry is mixed and ready - and just lightly mix it in.
A ratio of 1:3 or 1:4 is best for us. 1 part cement to 3-4 parts "other", which includes salt.
If you are trying Jiffy Rocks, do not remove the salt prior to baking.
And finally, realize that even the best made rock can still chip and shed once in a while. Moving it around in your tank, bumping it against each other (esp larger pieces), will inevitably cause bits to shed or chip off, unless you went for rounded ball like shapes, which seem to loose less, but also seem less porous and less attractive too.
I hope this helps a few people out there. I know that having something you worked hard on, that doesn't turn out like you wanted, can be disappointing. Hopefully this will help people understand what they should expect, and what they can do to correct it...
Well, I think that about covers my repertoire. I apologize for the length of this post, but hopefully some of you will find something of use…
I encourage the rest of you to take some time to write up your experiences and tips and share them with us â€"œ by sharing our experiences, we all learn and get better and better at making our own rock.
Good Luck, and Rock On!
:rollface:
Insane Reefer
New member
Well, cement doesn't finish hydration for "28 days", so basically it will still be doing the things that cause the high pH even after you remove it from the ocean.
As long as you continue the kure at home, I see no problem...
Insane Reefer
New member
Welcome to the Thread, NateDogg!
A lot of things that sound like they might work, do not. It isn't even so much about what is safe, but what will come out after all is said and done.
Take a marshmallow and put it in water. What happens? If it doesn't dissolve readily, chances are good that it won't flush from the rock...
Insane Reefer
New member
You need to provide a little more info to the others, Jeff, or at least answer the questions I posed you
bobbyblank
New member
Im sure its somewhere in this thread but i dont feel like reading 200 pages to look. When cureing the rock in water, what type are you useing? If you cure in tap water, all your going to do is saturate the rocks with phosphates which will leak into your tank for months to years. My LR was purchased from a person with a phosphate problem and the rocks have been leaching PO4 into my system for months. So are you cureing your rocks with RO/DI or saltwater?
Insane Reefer
New member
Actually, tap water is fine. I've done a battery of tests, on both white and grey rock, using RO/DI, tap and NSW, and found that using tap water to kure only raises the level of phosphates by maybe 0.01mg/l (in NSW test solutions), and those are quickly reduced by the primary algae bloom that the rock goes through.
If you still feel that there might be issues, using something like like Phos Zorb, PhosGuard, Phosphate Sponge or the like, in the kure bucket will probably help some.
You also have to realize that cement itself generally contains small amounts of phosphates, among other things - up to 2% can be pretty much anything you can think of, and still meet standards. Phosphates are usually mined in the same locations as the limestone and other materials that comprise portland cement - there is going to be some contamination
The cost of using salt or RO/DI would put rock outside most peoples price range - Travis once figured he uses about 1400 gallons to kure about 50-75lbs of rock.
MMLR isn't perfect, but neither is real live rock - there are pro's and con's to both. But if it makes you feel better, as far as I can remember on this thread, and a few others I've seen, only one or two people complained about phosphate problems or excessive algae growth (and one of those was probably due to the Oyster Shell used, come to find out), and many, many folks have made rock here.
That said, some of us use RO/DI, most of us use Tap, and a few of us use Salt Water.
If you still feel that there might be issues, using something like like Phos Zorb, PhosGuard, Phosphate Sponge or the like, in the kure bucket will probably help some.
You also have to realize that cement itself generally contains small amounts of phosphates, among other things - up to 2% can be pretty much anything you can think of, and still meet standards. Phosphates are usually mined in the same locations as the limestone and other materials that comprise portland cement - there is going to be some contamination
The cost of using salt or RO/DI would put rock outside most peoples price range - Travis once figured he uses about 1400 gallons to kure about 50-75lbs of rock.
MMLR isn't perfect, but neither is real live rock - there are pro's and con's to both. But if it makes you feel better, as far as I can remember on this thread, and a few others I've seen, only one or two people complained about phosphate problems or excessive algae growth (and one of those was probably due to the Oyster Shell used, come to find out), and many, many folks have made rock here.
That said, some of us use RO/DI, most of us use Tap, and a few of us use Salt Water.
goldmaniac
New member
I have some MMLR rock that's been curing in my garage, just sitting on shelves, for about 2-3 months, now.
5 days after casting this rock, I put it in water for 24 hours to release majority of the salt. then i put it back in my garage and it's been sitting there.
Hopefully, when I start the kuring process later this week, initial pH will start lower.
Anyone's thoughts? think my MMLR sitting in a garage for multiple months will cause a kuring thats faster than if it sat in my garage for 28 days?
G.
5 days after casting this rock, I put it in water for 24 hours to release majority of the salt. then i put it back in my garage and it's been sitting there.
Hopefully, when I start the kuring process later this week, initial pH will start lower.
Anyone's thoughts? think my MMLR sitting in a garage for multiple months will cause a kuring thats faster than if it sat in my garage for 28 days?
G.
Insane Reefer
New member
Hey Goldman
I don't think you will see a much lower pH for the first two or three water changes - it will probably be between 10 and 11, but you should see a rapid lowering after that.
And as far as a comparison between months and weeks, I'd say that both will kure (in normal situations) in close to the same time-frame - 2 to 3 weeks.
Keep us posted - I'm interested in the results
I don't think you will see a much lower pH for the first two or three water changes - it will probably be between 10 and 11, but you should see a rapid lowering after that.
And as far as a comparison between months and weeks, I'd say that both will kure (in normal situations) in close to the same time-frame - 2 to 3 weeks.
Keep us posted - I'm interested in the results
- Status
