Abstract: A swimming pool water treatment system for removing iron from feed water, with the system including a large storage/reaction vessel to which a branch injection/filtration circuit is coupled. An alkali metal hypochlorite is injected into water flowing through the injection/filtration circuit and delivered to the storage/reaction vessel to permit precipitation of the iron oxide. A bank of parallelly coupled filters are provided in the branch filtration circuit upstream from the hypochlorite injection site for removal of insoluble iron precipitated from the treated water within the storage/reaction vessel. The branch injection/filtration circuit further incorporates an ozone injector valve where a flow of ozone is continuously introduced to water flowing through the branch injection/filtration circuit. The storage/reaction vessel is sized sufficiently large so as to permit an adequate contact dwell time for formation of the insoluble iron precipitate.