Suitable for ponds up to 4,500 litres 1,000 gallonsthis uv filter has a unique easy clean mechanism meaning there is no need to take the sponges out of the filter simply turn the handle and watch the dirty water go to waste.backflush system you don’t need to lift the lid off this filter to clean it! Just operate the backflush system as follows br 1. Turn your pump off and turn the blue dial to ‘clean’. Br 2. Turn the handle to clean sponges and dislodge dirt. Br 3. Turn pump back on and dirty water escapes via the dedicated waste outlet. Br 4. Once the waste outlet water runs clear, turn your pump off and turn the dial back to ‘pond’. Br 5. Switch pump back 'on'cleaning indicator these filters include a cleaning indicator.in built uvc this pressurised filter includes a built in 11w uvc functionality, keeping your pond clean and clear for the long term!uvc bulb included.graduated foams included the pondxpert spinclean 4500 includes both coarse and fine foam filtration, which remove a significant amount of debris from your pond!please note  due to this models unique design, it does not require bio media balls.