Abstract: The invention comprises an improvement in a cleaning apparatus particularly useful for filters. A mechanism drives a hood into position adjacent partitions. A sealing member is selectively actuated to seal off at least one such compartment for cleaning while the remainder of the filter remains in service. Sealing is accomplished by interaction between the hood and the partitions. The invention also relates to techniques for selectively bringing the hood into contact with the partitions, and a construction of the hood and a media support plate which allows flexibility to lilft and scour the filter media using a gas to dislodge impurities, coupled with a liquid backwash involving drawing filtered water back through the media to carry away the impurities out of the filter.