Abstract: A main drain outlet and a water sanitation system for a swimming pool, wading pool, spa, or hot tub are provided. A main drain outlet comprises a cylindrical or toroidal sump, an inlet tangentially extending from the cylindrical or toroidal sump having an orifice with a length extending a longitudinal axis of the cylindrical or toroidal sump and a width substantially less than its length. The sump may have a curved inner surface throughout the length of the orifice. The main drain outlet may be of unitary assembly and may have more than one sump and inlet. The main drain outlet may comprise a testing strip. The pool water sanitation system may comprise skimmer flow equalizer lines in flow communication with a main drain outlet.

Abstract: A main drain outlet and a water sanitation system for a swimming pool, wading pool, spa, or hot tub are provided. A main drain outlet comprises a cylindrical or toroidal sump, an inlet tangentially extending from the cylindrical or toroidal sump having an orifice with a length extending a longitudinal axis of the cylindrical or toroidal sump and a width substantially less than its length. The sump may have a curved inner surface throughout the length of the orifice. The main drain outlet may be of unitary assembly and may have more than one sump and inlet. The main drain outlet may comprise a testing strip. The pool water sanitation system may comprise skimmer flow equalizer lines in flow communication with a main drain outlet.