Filterfalls™ biofilters come equipped with a swirl chamber, re-movable grate, media bag, and filter pad. Water pumped from the garden pond enters the biofilter from the bottom and proceeds directly into the swirl chamber. This area at the base of the biofilter is designed to distribute the water evenly throughout the filter for more efficient operation. Once the swirl chamber has been filled, water can then pass freely thru the filter mat and media. Water will eventually discharge from the filter onto a waterfall or proceed downstream. The Filterfalls 1000 biofilter has max flow rate of 2000 gph, a falls width of 14 inches, and a bulkhead of 1.5 inches.