My eco=system has nothing but MM, 3 small pieces of live rock, and the macro-algae (and the bio-balls in the first and 3rd chamber). I have never had to clean it. You don't need anything more then that (well, except for the pump and the light that stays on 24/7). By the way, if you ever have a piece of live rock that you want cleaned for some reason (like it gets some funky algae on it or something), put it in your sump with the macro-algae. It will be crystal clean (except for the coraline algae) in about 2 weeks.