Abstract: A filter apparatus wherein filter media is submerged in liquid being filtered and suction is employed under the media to increase the flow through it. The filter media in elongated strip form is supported on an incline for movement in one direction by an endless pervious conveyor. A receiving tank for dirty liquid is above the conveyor and media with a lower tank for clean liquid below the conveyor with the sides and ends of the lower tank being constantly sealed in order to maintain reduced pressure therein to enhance flow through the media. Filtered liquid is supplied at the sides of the conveyor and at an end wall of the receiving tank to prevent any migration of dirty liquid into the lower tank at the periphery of the lower tank. Advancement of the filter media is controlled automatically in response to variations in the pressure differential on opposite sides of the media which varies in proportion to the dirt load of the media.