Atlantic Water Gardens BF1600 Big-Flo Biological Filter is a Atlantic-branded product in the ownkoi catalog. Gravity-return biological filter from Atlantic Water Gardens. Includes coarse foam mechanical media and biological matrix; rated for ponds up to 1,600 gallons by the manufacturer. Specifications and pricing reflect the manufacturer-published or retailer-published data at the most recent catalog refresh. Verify the live listing on the source retailer page before purchase.