The Ultimate DIY Rocks!

[DeathWish302]

FWIW, gold's rock looks good....but making rock w/o softener salt will yield the same results with proper 'sprinkling' techniques and sand casting medium.

I don't know about the structural integrity of the rock in the long term, but if it works for some try it.

 

[cmpenney]

Yes it does look nice but as you stated proper techniques can yield the same results without salt. I'm not saying to experienced rock makers out there not to use it. In some situations I use it myself. There is just a narrow margin of error with salt and I don't think it should be recommended to beginners.

Let them get a few successes first. Then they can start playing.

 

[mr.wilson]

I know chemically salt is a bad idea, but from a practical standpoint many people have been able to use it in a fashion that doesn't allow the salt to dissolve quickly into the cement. Keeping the mix dry and adding the salt last seems to be the best method.

I have tried salt a few times, but it either dissolved in the mix, or made unnatural patterns. I think you need to cast the rock right on salt to get a natural pattern, but then strength and curing time (PH) will be a greater issue to contend with.

One thing for sure, is the first batch of rock anyone makes is going to be either recycled or buried in the reef.

 

[goldmaniac]

With respect, i just didn't agree with CMPenny's blanket statement not to use salt. That's all. I understand his/her points but there's so many ways and recipes that seem to work that there's room for multiple successful ways of making MMLR.

 

[goldmaniac]

and my first batch DID end up crumbling on me, as well ... but i ended up making multiple "batches" of pairs of those rocks, two at a time.

 

[vyerous]

So what's the consensus. I read the first 40 pages and the last 10 pages.

I want to do this but I want to make sure I didn't miss any live changing part of this.

I've got the portland concrete, already have made some in the past but didn't like the results, I want to use large granule rock salt however I really can't find any. I've found the water softening salt, perfect size but I'm pretty sure it won't disolve nearly as fast as rock salt would. I've talked to some people on my local forums and they suggested road salt, they said the chemicals in them are harmless to fish tanks, they have to be otherwise it would be illegal to put them on the roads where the run off could contaminate surrounding areas.

I figure I'll mix the concrete, get it nice and thick, pour in the salt last, have a tub full of salt with craters dug out, pour the concrete into nice shapes, cover with more salt, let its dry for 48 hours, soak in regular water doing water changes every day for about a month, soak in water from my water change to help cure and get some life on the rock, and add a piece of live rock from my sump to the bucket to help promote more life. Don't add to the display until the PH is constant and all params are acceptable.

I miss anything?

Also does anyone have a suggestion where to find the rock salt? I've been to tons of grocery stores, walmart didn't have it (didn't have mrs wages pickling lime either), I have no idea where to go. I live in northern VA if that helps.

Thanks!

 

[Electrobes]

I am surprised you came up with those steps (If you've read this thread). I don't suggest any of that. This is my opinion, so take it as you will. If anything look back to IR's super long posts that summarizes this thread.

Again this is my opinion, but based on experience.

- I don't suggest the use of salt. It retards the "curing" process. Sure some people have had longer term success with it's use, but overall it's suggested to not use it. For casting material I suggest you use sand (Be it quartz or aragonite).

- For the actual concrete, use something like perlite or dolomite instead of the salt. It'll provide more reinforcement for the rocks than using salt will... without retarding the curing process.

- After creating the rock (After mixing) you should wait 28 days for the curing process to "finish". Waiting 48 hours then submerging the rock will cause you many problems. The curing process will retard or halt altogether, and if you get the pH low enough.. the rock will probably fail in the aquarium.

- After the 28 days are over, then it's suggested to submerge the rock until you can get the pH to about 9 at it's max. You test the rock by putting it in old saltwater, leaving it for a couple days, stir up the water, then test the pH.

Hope this helps.

 

[DeathWish302]

....The curing process will retard or halt altogether, and if you get the pH low enough.. the rock will probably fail in the aquarium.

Christian - I was under the impression concrete will cure fine under water, but this soaking will remove the hydroxides which resulted in added strength...?:worried:

Just wondering if I have been misinformed or misread from the countless concrete pages I have viewed.... You are the expert along with Mr. Wilson on concrete...

 

[Electrobes]

I'm sorry I should have been specific... the difference between "curing" and "kuring"

"Curing", the process of hydrolysis of the cement, is best done outside of water. It is usually suggested that 28 days be given for the concrete to finish this process.

"Kuring", the process of leeching out the residual hydroxides that causes the water to have high pH.

A good way to say this, I guess, is the longer you let the "curing" process to last, the shorter the "kure" you'll end up needing. The Curing process uses up the hydroxides, and the Kuring process rids of the residual hydroxides.

Kuring is used to help the pH problem, not the strengthening of the rock. The strengthening of the rock comes from "Curing".

HTH

 

[DeathWish302]

No problem....

I knew the answer, and should have expanded on that.

As for the 28 day cure, it does work. I had some rock in the casting medium for nearly 2 months that was forgotten. I dropped this in the kure tub and 2 weeks later it measures below 9 (~8.8). My first rock that went into the water 72 hours after casting took nearly 6 weeks to do the same.

 

[vyerous]

The reason why I thought the salt was such a great idea, was because the pores it makes inside the rock. I've used the portland cement mixed with aragonite as the first attempt and it was relatively strong, now worse than "live rock" you buy in the store, I could still break it with a chisel and hammer relatively easy and the frag plugs could be broken with a pair of good pliars.

Like I said I wanted to use the salt inside the rock because it would disolve in the water and create the pores for more surface area and water flow if you will.

So you recommend using some sort of supplement to help make the concrete stronger, as in once cured the concrete just doesn't cut it?

Where could I find these? Is this something I have to order online? What ratio?

Thanks

 

[LobsterOfJustice]

Alright, so whats the ratio. I have some aragonite sand, silica sand, portland type 1/2 cement, and water softener salt.

 

[Electrobes]

It seems like people are starting to ask about stuff that was covered, here is IR's super long post (Final version, towards the bottom):

http://www.reefcentral.com/forums/showthread.php?t=1286738&page=21

Go through that and if y'all still have questions, don't be afraid to ask!

 

[Electrobes]

As some of y'all are aware, I am building a rock wall for my 40Br. I've been wanting to do one for a while but here is the brief pic history of it so far. The rock now sits "curing" and will be pulled out next month for the "kure" process.

The mix is 2 Perlite : 1.5-2 Aragonite : 1 Cement

Cure Process: 28 Days (Minimum temp of about 50F, but higher is desirable for cement/concrete)
Kure Process: Water changes until pH of 9 is reached (Max)

 

[Electrobes]

I knocked out the extra floor eggcrate, plus chipped off the edges of the rock so it will sit flush when put in the tank.

 

[mr.wilson]

Nice work Christian. I use small pieces of irregular shaped eggcrate mounted perpendicular to the main sheet (attached with cable/zip ties) to act as a rebar for more pronounced shelves and contour.

A back wall like that is a hell of a lot more realistic than glass covered in algae and fan worms.

 

[Electrobes]

Bugger, that's a great idea Shawn! Didn't think of that. It would have made casting a heck of a lot easier too I bet. :hmm2:

I am so looking forward to this wall when it's ready. Thus far I'm envisioning caps all along the back wall, with some of my soft corals at the bottom. Now that the wife demands sand instead of rock for the floor (Ain't being married grand? :lol: ), I may put a couple rocks on the floor for the rest of the soft corals... we'll see in about a month.

 

[mr.wilson]

Bugger, that's a great idea Shawn! Didn't think of that. It would have made casting a heck of a lot easier too I bet. :hmm2:

I am so looking forward to this wall when it's ready. Thus far I'm envisioning caps all along the back wall, with some of my soft corals at the bottom. Now that the wife demands sand instead of rock for the floor (Ain't being married grand? :lol: ), I may put a couple rocks on the floor for the rest of the soft corals... we'll see in about a month.

Putting a few holes in the back wall for pegging corals in place is a good idea. You can drill the holes later, but it's easier to poke them out with an acrylic rod while it's wet. This way you can glue a 1" rod into the bottom of your coral and peg it in place without need for epoxy.

I thought about doing this with magnets, but from what I have learned neodinium magnets have a tendency to rust even with zinc and epoxy coating.

 

[Electrobes]

I had thought about putting holes in the wall but realized that just about none of my corals have/use those type frag mounts. In fact, they all just have a piece of frag rock as their base.

The only thing on my mind now is the powerhead issue. On the one hand I'd like to carve out two holes for the koralias, but on the other once they're in.. that's it they'll HAVE to go there.

My only other option that I would consider would be to add an VorTech MP10... maybe carve out a bit of the side rock. I'll decide that later on... right now I am just happy the wall looks good.

Neodinium magnets.. is that was is sold at the big box stores like Lowes? I actually bought some along with some epoxy. It never occurred to me that the rock wall sits on it's own just fine. Maybe I'll use PVC for the magnets... make some shelves or something.

 

[DeathWish302]

The only thing on my mind now is the powerhead issue. On the one hand I'd like to carve out two holes for the koralias, but on the other once they're in.. that's it they'll HAVE to go there.

Neodinium magnets.. is that was is sold at the big box stores like Lowes? I actually bought some along with some epoxy. It never occurred to me that the rock wall sits on it's own just fine. Maybe I'll use PVC for the magnets... make some shelves or something.

I'm currently making a single prototype 'enclosure' for my Koralia 3. I have taken a balloon and surrounded it with a layer of 'crete. There are also several 1/2" holes for entering water and a 2-2.5" hole on the end for water stream exit. The back has had pop bottle caps in place during forming for magnet ports later after curing. It is still in the casting bin awaiting the 28 day cure, but I may be able to pull it out and post photos this weekend. I have also made coral cliffs that attach to the glass that add some dimension to the tank and break up the 'glass-box' look. This makes fragging a dream instead of soaking your arm every time!:thumbsup:

I buy all my Neodymium magnets from KJ magnets if you were asking where to buy. I have never found anything suitable for the price from big box stores. Remember strength is a plus, but a magnet with medium strength and a large surface area will be better than a very powerful small diameter magnet almost in every case.