The pond is about 1200 gallons with a max depth of 36" at the water falls. There is no bio filter and the water is pumped with a 2220 gph pump. When the pond was first put in I wanted a "waterfall" not some dribble of water over the falls. Well, the first pump we put in was a 4000 gph it gave us a roaring falls, unfortunately it also pulled all the floating plants, fish and snails into the skimmer and created such a splash pattern that it looked like the whole area was constantly raining.