fish and a small filter.? I need to set up a bacteria colony for my tropical Aquarium. I have lot of fish and a small filter. Can i put one sponge just below my filter where it sucks in the water from aquarium for filtering.Will this help to to setup a bacteria colony on the sponge.Since some times i will be away from Aquarium for bit long time, i can avoid the problem of generation of ammonia,nitrite and nitrate.Or Any other suggestion for setting up a very good bacteria colony.