I'm not sure that the Phosphate rumour is very well thought out. I say that now, but 1/4 of my tank is Marco rock so I hope that I'm right
Anyways, this is dry rock...it has no bacterial film or ecology to assist it with handling the phosphates that we add to the tank. When people say only my dry rock has algae on it...it's crap rock...I hope they remember that it's just CLEAN...of the bad and the good. Are there some rock's out there known for leaching, yes. Do they all do it...I just have trouble believing that.