Fecha de publicación: 10/08/2005 Fuente: WIPO "royal booby" A pump unit for placing in a pond, the unit comprising 10 a housing 40 in which is housed an electrical pump 70 and UV lamp 80. In operation the pump causes water from the pond to flow past the UV lamp so as to be exposed to the UV light. Such UV "filters" are used to remove the green colour due to algae growth, by causing the algae cell walls to rupture, and thus clarify the water. The pump unit may be submersible in water. The UV lamp may have a cover 86 of a material, such as quartz, which tends to allow UV light to pass through it. The pump unit may also have a mechanical filtering means (50 figure 3) removably located in the housing and a bypass means 52 for use if the filter becomes clogged. The pump unit may have a fountain 90 outlet and a flow control means 102 to variably control the flow through the bypass outlet and/or the fountain. Independently claimed are a pond pump and filter; a pond pump with variable flow control means and a pond pump with fountain outlet and bypass means.