Pond filter unit and a method for operating a pond filter unit (1). A control unit (12) controls the operation of the pond filter unit (1), including the cleaning cycle of the filter (2', 2", 2"'). The pond filter unit (1) further comprises one or more plugs (14) for connecting one or more auxiliary devices, such as a separate pump, one or more additional pond filter units, illumination means/lamps, air pumps, and/or feed automats. The control unit (12)of the pond filter further controls the one or more auxiliary devices connected to the plugs (14), such as pumps, air pumps, automatic feeding devices based on input settings for each of the one or more auxiliary devices. The control unit (12) further controls the cleaning cycle for cleaning of the filter (2) in the vessel (3). The cleaning cycle comprises a sequence of backwash and/or a mechanical filter cleaning sequence where a filter cleaning motor unit (6) rotates the filter cleaning device (7) in the vessel. During backwash, the valve (8) directs the water to the waste water outlet (11). The filter unit allows to control the one or more auxiliary devices by the pond filter control unit (12), and to coordinate the control of the additional devices in relation to the control of the filter.
