I do have a clean up crew as of two weeks ago,,,crabs snails and 2 surpant starfish,,,,I have lost quite a few of my crew though. I have 2 emporior 400,,,125 gal,,,2 powerheads. I use tap water and treat it for clorine and then add my salt,,,The tap water here is great as far as drinking it,,,it tasts good and for the most part I trust it,,,I forgot the meassurements but I think it is 1cc per gallon of the peroxide. It never hurt my clowns or my damsils,,,but I was told it will hurt inverts and some plants,,,,When I treated it turned all the black stuff to BRIGHT green color after about 12 hours,,,then in about 24 hours it was GONE,,,but always returned if I turned my light on. I went to my LFS and they said it was black slime,,,not algae and he gave me some red slime remover,,,it doesnt seem to have touched this problem so far,,,I treated yesturday with it and It apeears I havent done anything to it,,,It is coming back like mad,,,I think I will go back to the peroxide...