Our most advanced flow-through pond filter with an advanced 7 stage filter process, high power UVC and quick action de-sludge. At last we have found a box pond filter to satisfy the more discerning goldfish pond keeper. This box is even good enough for koi (see reduced pond size figures). This compact multi-bay system employs filter foam cartridges, brushes and flocor media to ensure your dirty pond water is thoroughly filtered. It has a powerful UVC unit built into the lids to keep your water clear of green water and is a doddle to clean due to the quick action back flush. A full de-sludge is also available by simple hose attachment - all filter media is held above the filter floor so valuable friendly bacteria will not be harmed by this process. NOTE: UVC bulb included.