The new hozelock ecoclear 5500 filtration system is a combined package including the new aquaforce 4000 pump and a bioforce 5500 uvc filterr bioforce 5500 uvc the bioforce filters are a closed pressure system holding more bacteria than a similar size normal filter small enough to hide near the pond when it is buried up to its lid this model also contains an ultra violet clarifierr aquaforce 4000 the new aquaforce is the recommended pump for pumping water to the bioforce filter and in ad