It is a sintered glass filtration media that houses billions of beneficial bacteria to get rid of ammonia, nitrite and nitrate. BIOHOME is by far the most operational and cost effective biological media available. Premium water quality through the use of an effective natural and environmentally safe biological filter is essential for the good health of fish and plants, and to eliminate dissolved nitrogenous compounds. With BIOHOME, you can be confident that generous colonies of both aerobic and anaerobic bacteria will be available to purify your water at all times