The pondxpert filtobox 12000 is suitable for ponds up to 12,000 litres 2,640 gallons. Maximum flow rate is 6,000lph.a genuine multi chamber professional gravity filter box that anyone can afford. We feel sure that these units will prove a hit. Dirty water enters through the multi stage hosetail at the top of the unit, passes through the uvc, foams and clean water leaves through the outlet pipe.sleek design a compact box filter that provides fantastic value. These smaller box designs are a sleek addition and easy to hide.easy maintenance simply lift the lid for easy access to the foams. Maintenance could not be any easier!bottom drain plug this filter comes complete with an integrated sludge outlet, which can be used to remove sludge from the base of the filter or do a back flush!mutli chamber cleaning system this filter features a multi chamber feature, where water is passed through several chambers full of foams and biomedia, ensuring thorough filtration.in built uvc  these filters include a built in 18w uvc functionality, keeping your pond clean and clear for the long term!uvc bulb included.