Pontec Pondorell 3000.Underwater Filter with Water Feature and UVC. This compact pump and filter unit is perfect for small ponds, the submerged installation means there will be no unsightly equipment spoiling the view of your pond. Ideal for ponds up to 3,000 litres without fish or 1,500 litres with fish stock. The compact underwater filter set combines 3 functions: The first function is to eliminate unsightly algae from the water by way of the integrated 7 watt UVC