Ultimate DIY Rock ?

djc1026

New member
Travis, the original thread is insane. Is your original recipe of 4:1 rock salt to portland cement #1 still your recommend recipe or do you have an updated recipe?

Dave
 
Isn't it? The thread is growing so fast I don't have time to stay caught up with it at work. :( FWIW, I recommend toning down the amount of salt to about 2-3 parts. 2 parts being stronger. You can add something like sand as an aggregate to give it more strength or even crushed coral/crushed oyster shell, but I still don't like the sharp texture that it offers. In addition, to help the overall strength, mix all your ingredients including the water together first before adding the salt. Any dissolved salt will slightly weaken the structure. Work fast as the more you work with it, the more the salt will have an effect. Another successful method at a shorter Kure time has been done with Perlite, but it doesn't leave the voids that salt does. Me and others are still working deligently on how to reduce the overall Kure time and still provide a good, porous, bio-live rock.
 
Um, while I recognize it cannot be authoritatively claimed that silica based sand will dissolve in a reef tank..... Have you noticed that Perlite is 70-75% silicon dioxide? Next highest ingredient is 12-15% aluminum oxide, another baddie for our tanks.

http://en.wikipedia.org/wiki/Perlite

I'd personally be concerned about using Perlite.
 
<a href=showthread.php?s=&postid=10608397#post10608397 target=_blank>Originally posted</a> by captbunzo
Um, while I recognize it cannot be authoritatively claimed that silica based sand will dissolve in a reef tank..... Have you noticed that Perlite is 70-75% silicon dioxide? Next highest ingredient is 12-15% aluminum oxide, another baddie for our tanks.

http://en.wikipedia.org/wiki/Perlite

I'd personally be concerned about using Perlite.
Yes, I realize that and I'm not a big fan of Perlite because it is just another wasted material in the mix, in my opinion, that doesn't matter if it works or not. If you would like more information on it in the use of reefs, then definitely skim through the DIY rock thread or PM Insane Reefer. She has done a fair amount of research in it and experimented as well. Unlike her, I'm still not convinced that it holds much helpfulness to MMLR.

On the other hand, the Quartz Crystal that makes up the predominate amount of Perlite is about the same as using play sand. In addition, the Silicates that do come out of the Perlite or even play sand help to bond to the Portland cement to make the C-H-S bonds. But, if you're looking to add silica to the mixture for improved strength and shorter Kure time, then you might as well add fly ash and stick with that. Plus, it is rather inconclusive whether or not silicates can come out of the silicon dioxide in play sand/perlite or if it comes from other areas. It is inert in freshwater, but I haven't heard reports about saltwater.
 
So 3:1 rock salt to cement? I don't have a need to add an aggregate. How malleable is the 3:1 compared to 4:1?

Dave
 
<a href=showthread.php?s=&postid=10612518#post10612518 target=_blank>Originally posted</a> by djc1026
So 3:1 rock salt to cement? I don't have a need to add an aggregate. How malleable is the 3:1 compared to 4:1?

Dave
FWIW, I would aim for 3:1, but I often over-water and have to add more cement. Sometimes I'm dead on, other times I screw up so much that it ends up being 2:1. The workability of any of these mixtures is more based on how much water is in the mix more than the components. I've never managed to get anything the consistency of playdoh for true sculpting, but you can get it to hold its shape rather well. If it is too wet, just add cement. If it is too dry, just add water.
 
Whats the average time it takes for the ph to come down enough to be put in a tank? I had about 20lbs of rock in a 55 gallon tank and changed the water when the ph went above about 9-10 and after about 2 months the ph still climbed.
 
Bad idea to kure in a tank. The kuring process can cause some horrid buildup of stuff on the container you are curing in. Good way to screw up a tank...
 
<a href=showthread.php?s=&postid=10627707#post10627707 target=_blank>Originally posted</a> by captbunzo
Bad idea to kure in a tank. The kuring process can cause some horrid buildup of stuff on the container you are curing in. Good way to screw up a tank...
agreed, sort of. It's much easier to kure in a seperate bin, but the build up is just calcium percipitate that can be cleaned with vinegar. It takes some effort and elbow grease, but it isn't permanent
 
<a href=showthread.php?s=&postid=10627413#post10627413 target=_blank>Originally posted</a> by jksteele010
Whats the average time it takes for the ph to come down enough to be put in a tank? I had about 20lbs of rock in a 55 gallon tank and changed the water when the ph went above about 9-10 and after about 2 months the ph still climbed.

You can cure it in under a week if you add 1/2 cup sugar and a packet of active yeast like you make bread with. It will create CO2 that will cure the cement and bring down the PH.
 
<a href=showthread.php?s=&postid=10629555#post10629555 target=_blank>Originally posted</a> by dugg
You can cure it in under a week if you add 1/2 cup sugar and a packet of active yeast like you make bread with. It will create CO2 that will cure the cement and bring down the PH.
The CO2 created by the yeast brings down the pH because it changes the water to carbonic acid. This will then degrade the outside of the rock slightly, so be careful. Make sure that the rock is properly Cured before attempting to Kure with any carbon dioxide or acid based methods. The initial Cure strength is crucial. Also, if you break open any rocks that aren't porous, make sure that you re-Kure it in a seperate bin. The freshly opened rocks will expose new, unKured layers. If you have a porous rock that water can actually flow through (IE Rock Salt Rocks), then the Kure might take a little longer depending on size and thickness of the rocks, but there is no fear in breaking it open.
 

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