The Ultimate DIY Rocks!
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reefnewbie54321
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i had kept updated with this threda for a long time but i havny been logged in for months ... i was skimming through and it was talkingabout baking your rocks? is this required for any reason ... i alreday made my firts batch with 2-3 parts salt and 1 part cement and they have been drying for 3 days now....should i bake them for any specific reason other then quicker drying or can i put them in the river behind my house?
Insane Reefer
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"They" are cement chemists and professionals...
Salt acts as a desiccant within the cement, removing "pore water", and ends up messing up the matrix of the cement in a very fundamental way, to put it simply. Salt tainted cement has a tendency to crack, craze and disintegrate over a few years time - a lot worse than normal, traditional rock made with no salt can eventually do.
I'm sure I'm not the only one that has notices that the number of people complaining about brittle rock has decreased since mixing the salt in was recommended to be done last. I certainly noticed a difference in friability and over all strength.
And you aren't the only one to say it - but why take a chance with adding the salt too early, knowing all that?
Salt acts as a desiccant within the cement, removing "pore water", and ends up messing up the matrix of the cement in a very fundamental way, to put it simply. Salt tainted cement has a tendency to crack, craze and disintegrate over a few years time - a lot worse than normal, traditional rock made with no salt can eventually do.
I'm sure I'm not the only one that has notices that the number of people complaining about brittle rock has decreased since mixing the salt in was recommended to be done last. I certainly noticed a difference in friability and over all strength.
And you aren't the only one to say it - but why take a chance with adding the salt too early, knowing all that?
Insane Reefer
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Did you do any water changes on this rock, Rick? A kure other than just sitting outside?
Anyway, stir that test container good, but if it still reads 7, and your rock has been in for a week or so? I'd say you are good to go.
A few people have been trying the air kure (I have a few more pieces too), and seems that air kuring might be almost as effective as water kuring.
More tests should be done - it would be nice for the traditional methods if you could get as much kuring by just leaving it alone as you would by wasting effort and water. Though you'd still probably need to flush some crud out, but a few water changes are better then a lot of water changes...
Unless you have access to a lab, and people who know how to use all the stuff in it, we are pretty much limited to the same things we test our tank for. Might want to test for Phosphates or Silicates, if you have them handy, or if your LFS will do the tests for you (some will, some may charge) - those might be interesting to see, but it is pretty much that or the "chuck it in and see if crap lives or dies" test...
Insane Reefer
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Michealalan I think it was, on another thread, said he had a friend who offered to autoclave a piece for him.
A pressure cooker would be awesome - would cook the rock just like the brick places do, but a home cooker would be too small to make it worth while - each rock would need 6 hours or so, and the cookers I have seen might hold 2 or 3 small rocks at a time...
BOKER420
Premium Member
My big rock pictured on the last page is actually at most 2-3 inches thick in any one place. I used a crock pot bowl upside down in the middle to give it a dome affect on the underside to take up space.
I just wanted to make a few big pieces because thats usually what I buy and I've spent 250-300 dollars on one piece of live rock a few times so a little more time spent on dispersing the salt out of the monster will be well worth it.
I'll have to try and make some smaller pieces now that I have the big ones out of my system. I found a big plastic serving tray that is shaped like a clam that I'm going to try and mold off of.
So if you were talking smaller rocks lets say 10lbs and less. What would be the amount of time it would take before they were good to go into a running system?
Insane,
Is the rock you sell the LFS's always ready to go into someones tank or do you sell it as uncured?
I just wanted to make a few big pieces because thats usually what I buy and I've spent 250-300 dollars on one piece of live rock a few times so a little more time spent on dispersing the salt out of the monster will be well worth it.
I'll have to try and make some smaller pieces now that I have the big ones out of my system. I found a big plastic serving tray that is shaped like a clam that I'm going to try and mold off of.
So if you were talking smaller rocks lets say 10lbs and less. What would be the amount of time it would take before they were good to go into a running system?
Insane,
Is the rock you sell the LFS's always ready to go into someones tank or do you sell it as uncured?
sunkool
New member
Again these chemists are looking for structural support and I could see where that would be an issue. They were not making liverock.
These rocks are not brittle and the rock is only going to get harder every day once put in the tank. The rock will absorb calcium from the water and be covered in coraline way before it has time to disintegrate.
Insane Reefer
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10lbs should kure in 4 weeks or less, if there is good movement.
Mostly it is unkured - I drop the price by 50 cents a pound just so I don't have to mess with it...
Insane Reefer
New member
You do it like you like
I've seen MMLR that went wrong long after it was added to the tank, and it didn't have salt in it.
But I'm sure you'll be fine.
If you'd like, I can link a few pdf's of research done on cement in saltwater - I think you would be surprised to find that it may not get harder everyday...
Rhodophyta
New member
"Structural support" is important to us too, unless we would be happy with live sand or live gravel instead of live rock. And if you've ever watched them build a highway or sidewalk, the structural support of concrete comes from the prepared ground and from steel rebar and grid.
I don't think there is any reason to imagine calcium being absorbed from the water by our rock. Unless we interrupt that process, the calcium in the rock is going to absorb the water of hydration if it can, something it does better in air and humidity. We are concerned with calcium leaking OUT of the rock, raising our pH.
dngspot
Premium Member
I have been using concrete rock for about 3 years. I love the stuff. I started with 40 lbs of Figi, I then made 300 lbs of concrete. After about a year it became difficult to tell what was concrete or Figi, except for the arches tubes and caves. The white rock is new rock made for my new tank, I just moved into a 210 rr.
I use 1 part cement, 2 parts pulverized limestone, 2 parts crushed oyster shell.
I use 1 part cement, 2 parts pulverized limestone, 2 parts crushed oyster shell.
Insane Reefer
New member
Very Nice Dngspot 
What recipe do you like to use? Is your rock made with white portland, or just 'white' by comparison?
You of course probably made the bulk of your rock without salt? Do you find that the MMLR is harder to keep 'clean' than real rock? You know - does it collect more crud that you have to blow out, than the real stuff?
I'm always interested in peoples' long-term results. So many folks get out of this hobby after less than a year, so it can be hard to collect data for longer usage...
What recipe do you like to use? Is your rock made with white portland, or just 'white' by comparison?
You of course probably made the bulk of your rock without salt? Do you find that the MMLR is harder to keep 'clean' than real rock? You know - does it collect more crud that you have to blow out, than the real stuff?
I'm always interested in peoples' long-term results. So many folks get out of this hobby after less than a year, so it can be hard to collect data for longer usage...
dngspot
Premium Member
The cement is standard portland 1. 1 part cement, 2 parts of pulverized limestone and 2 parts crushed oystershell. After the stuff is cured it looks light grey, when it is put in salt water it is bone white.
I have never cleaned this rock, or blowed out the surface.
Yes I did not use salt
Here is a blury image of a tube.
I have never cleaned this rock, or blowed out the surface.
Yes I did not use salt
Here is a blury image of a tube.
Insane Reefer
New member
LOL.
That's like saying an air conditioner absorbs O2...
Sunkool.
You are correct that since the rock will be in calcium rich water, that some of the calcium will be 'absorbed' by the rock - so will all the other things in the water, but sitting in the water and being filled by it, and actively removing calcium from the column, are two completely different things.
Our rock isn't going to remove calcium from the tank - unless you are counting the coralline algae using it up as it covers the rock.
If we have made our rock correctly, the process after hydration that occurs is 'cement carbonation', a process where-by free C02 converts the calcium hydroxide (high pH) to calcium carbonate (low pH). But this doesn't mean it has become a calcium sponge. Nitrates? Maybe. Calcium? No.
Just like our rock isn't going to add much in the way of calcium back to the tank. Water has to be very acidic to breakdown calcium from a calcium bearing source - our tanks do not get that low - hence the use of Calcium Reactors.
Insane Reefer
New member
Cool, Dngspot
Have any future rock projects planned?
Have any future rock projects planned?
dngspot
Premium Member
For curing rock I use a trash can that is hooked up to my ro waste water. I then drilled a hole in the top and installed a 1/2 inch barb fitting and siliconed it in place. I then attached a hose to it and put it in a floor drain. The hose from my ro sits on the bottom of the trash can. As the new water fills the bottom the old water exits the top and to the drain. It still takes 2 months to cure but I do not have to make the daily water changes.
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