Whitlam Flow-Aide Solution 6-Pack of Gallon Containers 6 x Gallon Flow Aide System Descaler Non-toxic concentrate which is certified to NSF/ANSI 60 for use in potable water systems Combining Flow-Aide with Isolation Valve Kits (Service Valves) will make the descaling process easy! Water scale deposits are a significant cause of heat transfer loss Even a thin layer of scale (1/32") can cause a 30% inc. in the cost to operate a hot water system