The PondXpert pond UVC steriliser exposes your pond water to powerful UV rays. These rays cause the microscopic algae to floculate (stick together) - forming larger particles which sink to the bottom of the pond, get picked up by your pond pump and then get caught in the pond filter sponges. Four models available, capable of clearing ponds up to a massive 40000L. All models include clear hosetails to fit flexible hose up to 40mm (1 ½") Clear hosetail's allow you to visually check the UV is operational External weatherproof ballast (attached ballast on 55w model) Wall mounting bracket included complete with screws Easy screw-release for bulb / quartz glass maintenance Suitable for ponds and aquariums (marine / freshwater) Hosetail's fits hose: 20mm, 25mm, 32mm, 40mm (¼", 1", 1¼", 1½) Specifications Greenstop 9000 (11w) For ponds up to 9000L UV Wattage: 11w Max Flow Rate: 4500 L/h Power Cable Length: 5m Greenstop 15000 (18w) For ponds up to 15000L UV Wattage: 18w Max Flow Rate: 7500 L/h Power Cable Length: 5m Greenstop 23000 (36w) For ponds up to 23000L UV Wattage: 36w Max Flow Rate: 10000 L/h Power Cable Length: 5m Greenstop 40000 (55w) For ponds up to 40000L UV Wattage: 55w Max Flow Rate: 20000 L/h Power Cable Length: 5m. The item "Greenstop Koi Pond UV Steriliser Filter Ultra Violet Clarifier Pond / Aquarium" is in sale since Friday, March 17, 2017.This item is in the category "Garden & Patio\Ponds & Water Features\Pond Filtration Equipment". The seller is "realaquatics" and is located in Aylesbury. This item can be shipped to United Kingdom, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Australia, United States, Canada, Japan, China, Israel, Hong Kong, Norway, Indonesia, Malaysia, Mexico, Singapore, South Korea, Switzerland, Taiwan, Thailand, Chile, New Zealand.