Abstract: A system for removing contaminants from water prior to supply to service by entraining a controlled quantity of air into the water to oxidize the contaminant particles and then filtering the contaminants in a combination aeration/filtration tank. The filtration tank includes an adapter which cooperates with a filter tank and the control valve for the filter tank to facilitate precipitation of water through the filter bed and venting of excess gases from the tank in addition to the filtering and backwash functions of the filter tank. The adapter is designed to cooperated with the control mechanism and tank of filter tanks used in currently available water conditioning systems.