Suitable for ponds up to 9,000 litres 2,000 gallons. Maximum flow rate is 6,000 litres.this pressurised filter is a joy to use. They are effective yet compact and they can be buried or located away from the pond. The pressurisation allows the option of running the water from the filter to the top of a waterfall.backflush system simply move the rocker from 'clean' to 'waste' and the water switches direction creating a backwash to flush debris to the dedicated waste outlet.cleaning indicator these filters include a cleaning indicator.in built uvc these filters include a built in 9w uvc functionality, keeping your pond clean and clear for the long term!uvc bulb included.graduated foams and biological media included the pondxpert easyfilter 9000 includes both coarse and fine foam filtration along with biomedia located beneath the foams which provide biological filtration.