The JBL Rapid Filter Cartridge ProFlow sf makes your JBL ProFlow u Pump a rapid filter system for effektive and rapid mechanical water clarification. After the running-in time the cartridge is biologically highly active. The special profile of the JBL ProFlow sf has a colonisation surface for cleansing bacteria from over 5 m.The cartridge is also an ideal inlet protection for JBL ProFlow u pump when used as flow pump in seawater aquarium. Used in connection with JBL ProFlow u and an interval switch, allowing virtually any cycle rate creating flwo conditions in marine aquariums as they occur in nature. Recommended minimum interval between two cycles: 10 minutes.