Seriously good pond filtration system from Oase. This set put together by the manufacturer includes the following Oase Biosmart 18000 Filter Old Biotec 10.1 Oase Vitronic 18w UVC Oase Aquamax Classic 5500 Pond Pump 5m x 112 hose 38mmThis set is a perfect pond filtration for goldfish ponds up to 9000 litres 2000 gallons. If keeping a lot of fish or a koi pond then the capacity is 4500 litres 1000 gallons.