Classic box filter without UV. The Hozelock Ecocel 5000 Pond Filter System is a compact and lightweight filter that can be used for ponds up to 5000 Litres, and can also be used in natural ponds. It filters water through foam and biological media and carries Hozelock's 'Clearwater' guarantee when combined with correct Vorton UVC. Includes filter media. This handy box filter system can bring added benefits to the fish and life living inside your garden pond. Suspended algae in pond water can cause unsightly and unhealthy water conditions, and in order to provide a healthy eco system it is recommended that some sort of filtration system is included in the pond. The Hozelock Ecocel is a popular choice, owing to its price and its benefits.