Even if you are swimming in your pool every day, a cartridge will last a minimum of two weeks, and much longer if you keep your pool covered and protected. Ideal for pools between 15ft and 18ft in diameter with 32mm screw fittings. 5, 678 litres per hour/ 1500 gallons (us) per hou.Supplied with two hoses with 32mm fittings. Takes size iii filters (part number 58012) - one supplied with pump. This is the UK specification 58389 fitted with a UK plug.