We have long been an admirer of the Oase Filtoclear range of pressurised pond filters. The patented Oase Easy-Clean cleaning mechanism really works and is a joy to use. If ever there was one thing that let them down it was relatively low power UVCs. Not anymore! This new 12000 introduced in 2013 boasts an 18w UVC and the extra UV power simply blasts away any algae/green water problem. This simple improvement has made this a highly popular and desirable filter - we have no hesitation in recommending this filter for any medium pond size.