Whitlam Flow-Aide Descaler Solution 1 Gallon1 Gallon of Flow Aide System DescalerNon-toxic concentrate which is certified to NSF/ANSI 60 for use in potable water systemsCombining Flow-Aide with Isolation Valve Kits (Service Valves) will make the descaling process easy!Water scale deposits are a significant cause of heat transfer lossEven a thin layer of scale (1/32") can cause a 30% inc. in the cost to operate a hot water system