I have a 29 gallon reef tank with 40lbs of LR 30 LBS of sand. PS. Ihave 6 small fish, 2 clowns, 2 PJ cardnals, 1 biocolor, 1 Lawnmover blenny. I've been have a red slime problem. the only thing that is out of wrack is my phosphates . very thing else is fine. My feeding is very very light and my lights are new.