For large ponds up to 2640 Gallons 12000 Litres.Fantastic value this filter comes complete with a powerful 18w UVC and comprehensive filter media. At last a genuine multi chamber professional filter box that anyone can afford. We feel sure that these new units will prove a hit.Dirty water enters through the multistage hosetail past the UVC where it is pushed through foam into the first chamber of biomedia. The water is then flows into a second chamber and is forced upwards through foam up and over into the final chamber.Clean water then returns.