TotalPond Pressurized Biological Filter Pressurized filtration system uses mechanical and biological filtration to clean your pond Removes debris, improves water quality while promoting the growth of beneficial bacteria Includes a coarse filter, fine filter and bio-balls For ponds up to 900 gallons; can be used in or out of your pond Must be used with a pump; Compatible with pump models DD11560, DDUV800, LLUV1050, or LL1200