Due to its unique shape, the Lifeguard Fluidized Bed Filter is an extremely efficient...high capacity biological filter. Beneficial bacteria attach to the media within the Lifegard Fluidized Filter...creating a thin film around the sand grains. Water is pumped through the unit...lifting the sand into a fluidized bed. The benificial bacteria attached to the media draw in dissolved wastes(ammonia& nitrate), oxygen supplied by Rainbow's exclusive water fall device and other required nutrients from the passing water converting them into relatively harmless nitrate. FB 300 Fluidized Bed Filter FB-600 Fluidized Bed Filter FB-900 Fluidized Bed Filter Most Orders Shipped Out Same Day! Premier Ponds LLC pondinfo@premierponds.com U.S.A. Copyright © 1999 - 2007 Premier Ponds LLC, North Salem, New York. All rights reserved. Thermo-Pond Heater 3.0, Aquascape Designs Pond Kits, ScareCrow Sprinkler, Nursery Pro Micro Pond Kits, AquaClearer, Microbe-Lift, Great Blue Heron Decoy, Pond Liners, Thermo Pond Heater & Deicer, Premium Koi Food, Select Koi, Butterfly Koi, Pond Aeration Pumps, Flexible PVC Piping, BioFalls, Skimmer, Aquascape Pumps, Cat Stop!, Animal Control Products, Pond Netting.