I have had no problems with clumping in my reactor, but keep in mind, my reactor is at a very low pH (around 6.3) and the limestone is supposed to be DISSOLVING, not precipitating under these conditions. It is possible that the dreaded sand--->concrete phenomenon could occur with this sand (a form of calcite I believe) when used as a substrate, but I'm not sure if it is any more likely than with a fine aragonite substrate. Hopefully Randy will give his opinion. I believe that the substrate--->concrete conversion is most likely to take place in a tank with a new, very clean sand bed (i.e. particles not yet coated with proteinaceous substances), and aggressive use of calcium additives keeping the alkalinity and calcium levels very high.
I have not used this sand directly in a tank, but I don't think there will be a problem. The Home Depot sand is available here in Boston, so I use that for the most part. FWIW, the limestone sand is much easier to rinse out than the typical fine aragonite sands.
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- Greg Hiller
need frags in the Boston area? E-mail me