Biological Filtration

Biological filtration uses bacteria to remove ammonia and nitrite contained in fish urine from the water. At Pentair AES, we carry a range of biofilters for your aquaculture tank or pond, including sponge filters, fluidized bed filters, bead filters, low-space bioreactors and pond bio filters. We also have a complete selection of biological media.
Sponge filters are a type of trickling biofilter; as water flows through the sponge, a layer of biofilm forms. This film then removes ammonia and nitrites from water that passes over it, while the sponge itself helps to capture solids. Bio-balls, bio-barrels, and other plastic bio filter media work in a similar way — these media are contained in a filter bag or other container and provide a base on which the needed bacteria can grow. It's important to provide space between the surfaces of the media to allow bacteria to grow and water to pass.
Fluidized bed biofilters and bioreactors work slightly differently. A fluidized bed filter typically uses wet sand in a container as a base for the bacteria to grow, providing a compact and self-cleaning filter system. Bioreactors — sometimes called moving bed biofilm reactors or MBBRs — work in a similar way, although they typically use an HDPE polymer media that is less likely to experience disruptions caused by variations in the water flow rate or power failures. Air rather than water is used to circulate the media in this type of biofilter, eliminating the need to oxygenate the water.
If you have questions about choosing a pond or aquarium bio filter, please call our experienced team at 877-347-4788 or ask us. We'll be happy to help you determine which biofilter is right for your fish holding tank or pond.