I have a dozen red-leg hermits, a dozen cerith snails, and an emerald mithrax crab who do a great job cleaning my 29 gallon FOWLR. The hermits, however, have been doing too good of a job lately and are trying to clean all the coraline off my rocks as well, so you may want to use less of them or try a different kind. Maybe someone else will have some other good ideas.