ewurm;637315; said:It's probably just mineral deposits, like calcium and sodium, probably harmless.
jerppyjerp;637550; said:Now here's the thing...I've always had hard water. It was only till I was dropping the ph for my rays when I noticed the build up. I'd disregard it if it wasnt so gross-looking on my black sand. The contrast sucks cause I have black sand and this whiteist grey crap all over the ground. If fish dont typically eat things that are bad for them why do they insist on tasting EVERYTHING!!!