Abstract: A pump and filter assembly suitable for circulating and filtering swimming-pool water is provided with a normally closed air-injection valve to aerate water flowing into a filtration element in the filter. When the exterior surfaces of the element become covered with dirt or filter cake, the air-injection valve and an auxiliary filter outlet are opened. Air aspirated through the valve into the filter inlet water stream causes a churning cleaning action which dislodges the dirt, and the debris-laden water is discharged through the auxiliary outlet without passing through the element.

Abstract: A skimmer filter and pumping unit for an above-ground swimming pool including portable pools in which a centrifugal pump is mounted on a base beside the pool. A cartridge-type filter unit having a cylindrical housing is supported from the base above the pump with the pump and cylindrical housing aligned along a common vertical axis. A skimmer unit is mounted on top of the filter unit and has an opening in the side adapted to open through the side of the pool adjacent the top of the pool when the base is resting on the ground. Water moves directly through the skimmer unit down through the filter into the pump, the pump dishcarge being connected back through the side of the pool below the skimmer.

Abstract: A portable spa in which a confining outer wall rests on the ground or other flat surface. A water impervious liner is suspended from the top of the wall and forms a barrier for holding water. The liner is formed with a double-wall construction with an inner sheet attached around the margins to the outer sheet to form a confined space. A pump for recirculating water through the pool has its outlet connected through a conduit to the confined space so that water is forced into the confined space under pressure. A portion of the inner sheet is shaped to form a raised seat on the bottom of the pool when inflated, while another portion of the inner sheet extends above the seat to form a back rest when inflated. The pump directs water through a series of jets through the sides of the pool to provide a massaging action.

Abstract: Apparatus for indicating when a swimming pool filter needs to be cleaned, which comprises a flexible diaphragm covering an opening in the conduit on the inlet side of a pool filter and a housing covering the diaphragm with a movable piston member inside the housing and engaging the surface of the diaphragm. Spring means urges the piston against the diaphragm to counteract pressure of water in the conduit against the diaphragm. A movable flag is operated by the piston means to indicate through a window in the housing when the piston has moved a predetermined distance.