The Swell Pressure Filter Premium is an energy-efficient, pressurised pond filter with UV lighting and re-usable foams. Suitable for garden ponds up to 20,000 litres, these filters are equipped with biological and mechanical filter foams that enable the rapid growth of aerobic bacteria. Cleaning is made easy thanks to their internal foam cleaning mechanisms. They come with a 5 m cable and can be buried out of sight. They can also be ran year-round and, thanks to the fact they're pressurised, they can pump water uphill against the force of gravity. This is great for ponds with waterfalls. This model has a unique feature that tells you when the filter needs to be cleaned by using a small float, which pops-out of the head of the unit when required. By simply turning the handle you can clean the interior sponge. This keeps manual cleaning to a minimum. After cleaning the sponge, the outlet can be opened to discharge dirty water until it runs clear. How To Clean: - Turn off your pump, then remove the blanking cap over the sludge outlet and place this over the clean outlet pipe. - Turn the blue dial to clean mode and crank the handle. This compresses the filter foams and squeezes out any built-up debris. - Turn the pump back on. This will back flush the dirty water. Once clear water comes out of the sludge outlet, turn off your pump - Put the blanking cap back over the sludge outlet, turn the dial back to clean and turn the pump back on. This process is relatively quick, taking around 5 minutes. It's recommended that you clean your filter foams using this method at least once a month. Please Note, failure to maintain the filter regularly could risk damage to the internal cog system.