Due to its unique shape, the Lifegard Fluidized Bed Filter is an extremely efficient high-capacity "biological" filter. Aquatic organisms excrete toxic ammonia as a metabolic waste product with additional ammonia produced as food and other organic matter breaks down and decomposes. Beneficial bacteria attach to the media within the Lifegard Fluidized Bed Filter, creating a thin film around the sand grains. Water is pumped up through the unit, lifting the sand into a "fluidized bed". The bacteria attached to the media utilize dissolved wastes (ammonia and nitrite), oxygen supplied by Rainbow's exclusive water fall device and other required nutrients from the passing water converting them to relatively harmless nitrate. The sand grains are in continual free fall through the water resulting in an excellent transfer capability between the water and the bacterial film on the media. The enormously high surface area combined with this excellent transfer capability creates the perfect habitat for bacterial growth. In addition, the sand grains bump into each other frequently knocking off excess debris and providing a self-cleaning function which allow new areas for bacterial growth.