Fluidized Bed Aquarium Filters are a unique type of biological filter. Usually columnar in form, they use a fine sand or media, which is suspended or fluidized by forcing water through it inside of the filter. This Fluidizing of the fine filter media allows for an extremely high surface area for bacteria to colonize, which consumes the nitrogenous waste in the water at a extremely efficient rate. The high surface area to volume ratio of the filter media, allows for Fluidized Bed filters to filter large volumes of water, with a relatively small filter size.