Abstract

A vacuum filter is provided for vacuum flow filtration through a filter bed of water from a swimming pool including flow from the pool and from the gutter of the swimming pool, and controlling water recirculation capacity to accommodate varying gutter flow, comprising a tank; a filter bed of particulate material in the tank; a first inlet line communicating the swimming pool with the tank for gravity flow into the tank and maintaining a predetermined level of water in the tank in relation to a level of water in the swimming pool, thereby providing a head of water for gravity backwash flow through the filter bed; a second inlet line communicating the tank with the perimeter gutter for the swimming pool for gravity flow into the tank; a third inlet line communicating the tank with the perimeter gutter for the swimming pool for suction flow into the tank; an outlet line communicating the tank with the water recirculation system; a pump drawing a vacuum downstream of the filter bed and recirculating filtered water to the swimming pool; valves controlling flow into the tank via the first, second and third inlet lines; and at least one water level-responsive sensor sensing and directly responding to the level of water in the tank and adjusting the valve controlling suction flow, to increase gutter drain flow to the tank sufficiently to prevent gutter water flooding back from the gutter to the pool.