Dominion Water’s Aeration Iron System uses a compact patented air injector piston built into the Fleck control valve to oxidize iron, manganese, and rotten egg odor caused by hydrogen sulfide gas. These naturally occurring elements can be removed from your water using the natural process of oxidation. The aeration filter maintains an air pocket in the top of the tank and as water passes thru the air pocket, the iron, sulphur and manganese are oxidized. The oxidized elements are then filtered out as they pass thru the filter media in the tank. There is no need for harsh chemicals. This system can remove up to 8 ppm hydrogen sulfide gas and up to 7 ppm iron and manganese. The filtration tank is automatically backwashed during low water usage times of your choosing. How often the filtration tank backwashes is determined by the amount of iron, manganese and hydrogen sulfide gas in your water as determined during your free water analysis.