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Do I need an iron filter? When iron is present in a water supply, it is quite evident; because iron-bearing water readily stains plumbing fixtures and cooking utensils. Laundry washed in iron water soon becomes stained a reddish brown color. It imparts a metallic or medicinal taste to the water and beverages made with this water have an unappetizing inky black appearance. The flavor of coffee, tea, or other drinks is ruined. This in turn forms a hydroxide commonly called rust that stains fixtures and clothing as it fouls softener media. When iron precipitates, it discolors the water yellow, brown or red. It accumulates in pipes, meters and valves, frequently reducing the flow rate capacity. Iron can also reduce the capacity of ion exchange resins. Iron is dissolved by ground water containing carbon dioxide, but little or no oxygen. When rain percolates into the soil, dissolved oxygen is removed from the water in the decomposition of organic matter. Generally, the lower the water’s pH, the higher the iron content because the iron compounds in soils and rocks are dissolved by the acid water. Acidity is generally higher (lower pH) in naturally soft water areas since carbon dioxide picked up from the soil has not been neutralized by limestone. These soft water areas will tend to have more "iron water" than hard water areas. Ferrous iron Ferrous iron is usually found in water drawn from wells. Ferrous iron is iron in solution and remains in the ferrous state as long as the water remains underground, where oxygen is scarce. Ferrous iron is typically colorless with a distinct iron taste. When water containing ferrous iron is exposed to the air, the carbon dioxide escapes and ferric iron is formed as oxygen enters the water. This soluble iron is red-orange colored. Eventually, this precipitant will settle to the bottom of a container. Iron is rarely found in surface water since iron oxidizes upon exposure to air and settles out. When surface water does contain iron, the water is usually very acidic. Bacterial iron Another type of iron is bacterial iron. This type of iron can live in light or darkness. Bacterial iron causes the development of gelatinous masses around well screens and in plumbing lines, as well as creates objectionable odors. Problem iron can be removed from water through ion exchange water softening. Unfortunately, phosphates and other agents that are used to keep iron ferrous also disrupt ion exchange, enabling it to bleed through the softener bed. Tannins or other organics may also hold iron, preventing it from properly exchanging. Oxidizing agents like chlorine, potassium permanganate, and aeration precipitate iron to its ferric state, also preventing it from being exchanged onto the media. When installing softeners, don't use systems with top screens or strainers on the inlets. Iron particles oxidized on the bed can accumulate and clog screen openings. Hard water deposits can also build around screen openings and cause pressure drops. Occasional chemical cleaning of resin may be needed, but chlorine shouldn't be used. Acids usually work better, but be extremely careful when using them. Non-toxic cleaners, like salt additives and chemicals fed into the brine tank as a preventive maintenance measure, usually can't clean a badly fouled unit. Potassium permanganate is a good oxidizing agent that usually precipitates iron in larger particles than chlorine. Greensand media is also used to oxidize iron. It can fail however, where tannins, heavy sulpher, low pH or high flow conditions exist. Greensand usually requires regeneration with potassium permanganate, which is messy and potentially toxic. If
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