What is a biologic filter?

What is a biologic filter?

• A. An inert substance that is a substrate which binds nitrifying bacteria
• B. A carbon-activated filter
• C. A filter that employs a constant stream of water
• D. An ultraviolet filter used in static tanks

Answer: (A)

Biological filtration relies on beneficial bacteria living on a surface to break down waste. A biologic filter supplies an inert, porous substrate that provides a lot of surface area for nitrifying bacteria to colonize. These bacteria then convert toxic ammonia from waste into nitrite and then into nitrate, helping keep the water safe for the animals. Because the medium is inert, its role is to host the bacterial biofilm, not to chemically remove substances or disinfect the water. The other concepts describe different filtration approaches—carbon filters remove organics by adsorption, a filter with a constant water stream is describing flow characteristics rather than biology, and ultraviolet filters kill microbes with light rather than support a bacterial colony.

Biological filtration relies on beneficial bacteria living on a surface to break down waste. A biologic filter supplies an inert, porous substrate that provides a lot of surface area for nitrifying bacteria to colonize. These bacteria then convert toxic ammonia from waste into nitrite and then into nitrate, helping keep the water safe for the animals. Because the medium is inert, its role is to host the bacterial biofilm, not to chemically remove substances or disinfect the water. The other concepts describe different filtration approaches—carbon filters remove organics by adsorption, a filter with a constant water stream is describing flow characteristics rather than biology, and ultraviolet filters kill microbes with light rather than support a bacterial colony.