Biological filtration by colonies of beneficial bacteria remove toxic ammonia, ammonium and nitrites. PondPads provide the perfect substrate for bacteria in the ProfiClear Compact Moving Bed Module. Massive surface area of PondPads breaks down almost four times as much waste per unit volume as Hel-x 13 bio-media. Every 10 liters of PondPads can decompose approximately 9 oz of food waste per day. Each bag contains 10 liters of PondPads.