Abstract: A drain sump includes a secondary chamber for providing an alternate source of water for the main drain to pull water from, thereby limiting the suction force created when the flow of water is obstructed. In a preferred embodiment, the two chambers within the drain sump are partitioned by a septum wall, which provides a passage for a drain pipe extension at the center of the septum wall and further includes a plurality of venting channels for ideal water flow between the two chambers. Each chamber is in open fluid flow communication with the pool water via the drain grate. Relief hole passages are included on the drain pipe extension for providing open fluid communication between the secondary chamber and the water flow passage. The drain pipe extension may further include two 90 degree bends for restricting access to the water flow passage of the drain pipe extension.

Abstract: A drain sump includes a secondary chamber for providing an alternate source of water for the main drain to pull water from, thereby limiting the suction force created when the flow of water is obstructed. In a preferred embodiment, the two chambers within the drain sump are partitioned by a septum wall, which provides a passage for a drain pipe extension at the center of the septum wall and further includes a plurality of venting channels for ideal water flow between the two chambers. Each chamber is in open fluid flow communication with the pool water via the drain grate. Relief hole passages are included on the drain pipe extension for providing open fluid communication between the secondary chamber and the water flow passage. The drain pipe extension may further include two 90 degree bends for restricting access to the water flow passage of the drain pipe extension.