The Ultimate DIY Rocks!

[Insane Reefer]

<a href=showthread.php?s=&postid=10995363#post10995363 target=_blank>Originally posted</a> by tankslave
I'm finding that the problem with much of the DIY rock is that it is not very porous, and hence not very good (at least all the recipes that I've tried). I'm not looking for "holey" rock, there's plenty of that, but truly porous, something that will colonize anaerobic bacteria.

Indeed, holey and porous are two different things

I have run across this problem when the mix I make is too wet. The dryer the mix, the more porous it tends to be. Also note that salt can sometimes give a sort of "slick" finish to cement that can act as a water barrier, so be careful with over mixing. A new test I think works pretty well is to pinch off a bit of your mix and gently rub your thumb over a section of that for a few seconds. Does it get shiny fairly quickly? If so, then your mix probably has too much water in it.
But that is just the most common reason I find for less then porous rock. There are others, I'm sure. Packing the cast too tightly will make dense rock...

<a href=showthread.php?s=&postid=10995591#post10995591 target=_blank>Originally posted</a> by SWINGRRRR
Insane, what are you using to mold them? Sand. I like how tall they are. I am having difficulty finding filler material. The rock salt is $5/40lbs bag. Id probably need 10 bags to fill up the Steralite Tub I have.

Yes, sand. Unimin Industrial Quartz, which is finer than sugar-fine I think; it is made for filtration and sandblasting. It claims 99% purity. It blends into the surface of the white cement and you really have to look to see it most places. I get mine at ACE Hardware for $7 a #75. I can recycle about 95% each time I use it, so don't have to replace it very often.

 

[SWINGRRRR]

Thanks. i am going to one of the local Mom and Pops places tomorrow. See what they have to offer. I didnt even remember the place till you said "Ace HW"

 

[kraze3]

IR some great shapes there. Waiting to get a new bag of portland so I can make more.

 

[impur]

Indeed great shapes IR. I'll cast my next one in sand and see how it turns out.

 

[Insane Reefer]

Thanks guys

I'm a big fan of casting in sand. Granted you don't get the pores on the outside as you do with salt, which do look cool, but the sand is so much easier to work with; you can shape the wet sand and it holds a shape better then salt can.

 

[mmm55645]

I have had several rocks will cement colorant water curing for quite some time.

I did not notice the water to be red color or look any different than water from rocks without colorant.There is still time for the water to change, I guess.

I am yet to contact quikrete, but i will eventually.

I haven't gotten a chacne to see what the limestone is like around here yet, either. there are quite a few quarries though.

I need to check out some of the specialty stores too. Hopefully I will find some interesting types of cement there.

I will let the board know about any progress or info with the cement colorant rocks.

 

[mmm55645]

__in the last post I meant to say with instead of will in the first line.

one other thing, I have some normal olskool rocks that have been air cured for ~2months and water cured for ~2 months.

My wide range pH test strips read 7 or 8, and another test strip I have reads 8.4. it would seem like the pH would be stable by now, but I don't want to take any chances.

I am not sure exactly what to do, other than buy another way to test. I am thinking about buying one of those constant ph devices.

any suggestions?


oh and another thing- IMO the Walt Whitman Live Rock looks like it was colored with cement colorant. Does anyone know how that rock is produced?

 

[Insane Reefer]

MMM.
If the rock were going to bleed, it would be doing so from the get go. That it isn't is a good sign that at least the color is going to stay put. Now, as the rock carbonates, it will dull down to a chalky, lighter colored version of what you have - I think it will look good.

If two different test kits say that it is no higher then 8.4, I'd say you are ok, esp if you are testing with both at the same time. One of those test kits wouldn't be for saltwater, would it? Not sure if there are salt -vs- fresh tests or not, but that might throw a reading.

And yes, WS makes some rock that is colored purple. Not sure what colorant he is using, but maybe you could email and ask?

 

[mmm55645]

IR, the wide range pH test strips did not indicate if they were for salt or fresh, and the other strips were for fresh water. For some reason I assumed, perhaps incorrectly, that the wide range pH strips were for water.

The rock that I have water curing with leaves looks pretty nice. It is a dark brown color. I have no idea if the color will stay on the rock or not but atm it looks pretty good. I will post a pic of it when I get a chance.

Forgive my ignorance, but I am kinda confused about porosity and colonization of bacteria in MMLR.
If I remember correct, I read a while back that dense rock aids in the colonization of bacteria, but a different kind of bacteria than porous rock. I am thinking of the pictures of the dense rock Mr. Wilson posted.
If you break apart rock to determine whether it is holey or porous
how can you determine what the ideal porosity is? Should there be many small holes and not large ones?
If the rock is dense-- does that mean that it will not work as a bio-filter in a reef tank? Are the sorts of bacteria that colonize dense rock not wanted for our purposes of bio-filtration from the rock?
I am thinking that much of the rock I made had a wet mix and is somewhat dense, does this mean that this rock will not be effective(or even become) LR in a tank?

One more question, which is strange and probably entirely foolish, but here goes,
regarding a frame for rock, I am curious about those metal racks that are coating with some kind of plastic. I dont'[ know what they are called but you can buy them to build racks or shelves, they are usually white.
Would these pieces of coated metal(I don't know what to call them really) be analagous(on a small scale) to epoxy coated rebar? The coating on the pieces looks like some kind of plastic and if that plastic is similar to the epoxy on epoxy coated rebar, it follows that it could be used to construct reinforced concrete-MMLR that could be underwater.
If the material is safe it would be much stronger for building strange rock shapes than pvc pipe.
I don't know enough about materials to know if the coating on the material is similar at all to the epoxy coating on rebar.

 

[Insane Reefer]

<a href=showthread.php?s=&postid=11009564#post11009564 target=_blank>Originally posted</a> by mmm55645
For some reason I assumed, perhaps incorrectly, that the wide range pH strips were for water.

They are - just wanted to verify that neither were for saltwater in particular. Not sure why there would be such a difference, but I'll stand by my thought that they are still in the safe range, either testing method.

Forgive my ignorance, but I am kinda confused about porosity and colonization of bacteria in MMLR.
If I remember correct, I read a while back that dense rock aids in the colonization of bacteria, but a different kind of bacteria than porous rock. I am thinking of the pictures of the dense rock Mr. Wilson posted. ...I made had a wet mix and is somewhat dense, does this mean that this rock will not be effective(or even become) LR in a tank?

Good question, and I wish someone could answer your question with authority, but ATM, it is pretty much all guess work. Not much in the way of real research has been done with LR, beyond private experience and experimentation with it.

LR actually provides (or should provide) the habitat for two basic types of bacteria - aerobic and anaerobic. The aerobic types will colonize almost anywhere in and on the rock and sand that it can - these bacteria turn Waste into Nitrites and Nitrites to Nitrates. The other, anaerobic bacteria, colonizes deep in what I think are called "cryptic zones", which are basically low/no o2 zones - these zones are typically deeper in the rock, and at the bottom of our sandbeds. - and these bacteria are responsible for turning Nitrates into harmless Nitrogen gas.

So IMO, the porous rock we tend to get from these recipes, if made correctly, should provide both places for bacteria. Any rock of this type that you make, should be capable of housing bacteria, and hence become "live rock", but what exactly makes it that is sort of up for discussion until scientific, peer reviewed research is done...

One more question, which is strange and probably entirely foolish, but here goes.

No such thing - only stupid answers

Would these pieces of coated metal(I don't know what to call them really) be analagous(on a small scale) to epoxy coated rebar?

Sorry This is completely out of my area of knowledge - I'll have to defer it to someone else. My main concern/thought would be, is the plastic coating made with food grade plastic? Many plastics leech toxins from the dyes used to color it. Other then that, ???
Anyone else?

HTH

 

[kraze3]

I dont think i would try the coated metal stuff. There is always a possibility of the plastic ripping or being torn somewhere down the line as well as possible toxin leeching as IR said above.

I think pvc is more than strong enough to hold your MMLR molds. Pvc is pretty strong although it may not look it. Sinks, Showers, toilets, etc are all plumbed with pvc. Ive even seen many shelfing units made to hold auto parts or tools using pvc for the stands and then plywood for the shelves. If its the hollows inside the pipe that worries you, drill a few good sized holes in them and fill the inside of the pipe with your MMLR mix too. No reason to waste the inside diameter and it will make it that much stronger too.

 

[SWINGRRRR]

This is the biggest by far, so far. This is from the second batch. There was another one cast in the second batch, but it just looks like a rock. This is is my favorite so far. I just hope they are porous enough. I think my salt is to big.

 

[Insane Reefer]

Nice work, Swingrrr

Porosity really has more to do with what you use for cement, and how wet or dry you mix it, from what I've read, and IME. Excess moisture in the mud can also be partly responsible for high pH.

Most of the rock we make will work just fine - the more porous stuff will house the aerobic bacterias and the denser, less porous stuff will house the anaerobic bacteria.

Or at least that is my reasoning...

 

[SWINGRRRR]

Thanks dude. I have been going for as many caves, back to back caves () and as much surface area as possible. Tomorrow I am going to knock out a third batch and try to make it lump out of my hand. Like making sand castles, if you know what I mean.

 

[SWINGRRRR]

You know, I didn't read all of the plastic coated metal post, but I know I should. Something crossed my mind though while researching the MJmods. There was a link to "Epoxy Coated Disc Magnets" I know these are very small, but its still a type of coated metal in your tank, well some tanks.
Ya'll see what I am saying? I wonder if theres a way to get 2 part Marine Epoxy to stick to metal. And then you could use that as a very strong "skeleton" for anything you wanted to make.

 

[2004jeepoutlander]

I love to make "acro table" rocks i think they will sell very well..

 

[Insane Reefer]

How about a few pictures Jeep?
We love pictures

 

[mmm55645]

I joined some of my rocks together with water stop cement. In about a week I am going to put them into my tank.
I am starting a new tank. Does it make any difference if the rocks are in the cycle at the beginning or after the tank is cycled? The rocks should go in before the cycle starts, correct?
Anyone use one of the fast curing cements to join rocks together and if so do you use the cement and an aggregate or just the cement?
I will post a few pics of my finsihed rocks soon.

 

[Insane Reefer]

It will take a while for your rock to become "live", so yes, start it along with the tank. Seeding with sand from a trusted source will get the ball rolling, or just order up a GARF Grunge pack - I hear those are pretty good. Keep the load light for the first 6-9 months, and you will have nice LR.

 

[airinhere]

Insane reefer, you have PM.
And I am looking for Mr. Wilson and Travis also. So they should have PM.