I went today to this landscape supply store & got about 70 lb of Moriah pancake stones. I really did'nt look at them to good & when I got home & started to clean them I notice some kind of plaster or paint on the bottom of the stone. I was wondering how to clean them so they can be safe to put in my tank?
i would be really leary of adding that to your tank for the moment, until you can identify what the stuff is on the bottoms...
i'd take one of the stones and soak it in a bucket of water for a day at least, see if it changes the water color.
does the stuff scrape off? it could be some sort of landscapers' water sealant. honestly it sounds bad to me. maybe do an acid test on it, vinegar would work. if it bubbles, it might be a lime based plaster and you are gonna want to get it off.
what is Moriah pancake stone, anyway? some sort of slate?
