The Blagdon Midipond UV Pond Filter System 20,000 is a seven-stage luxury pond filter designed to provide clear and healthy water for large ponds up to 5,625 Litres. It features a professional 7-stage filtration process for minimum maintenance. Create spectacular waterfalls with its 4 outlets, capable of handling high flow rates. The venturi oxygenation chamber adds oxygen-rich water, creating an ideal environment for beneficial bacteria. The built-in UV clarifier ensures algae-free, clear water. Maintenance is easy with a large hinged lid, lift-out Hydroscreen pre-filter, 3 grades of open-cell foam, ceramic bio media, and replaceable polymer wool pad. Carbon impregnated foam removes chemical pollutants.