How do Iron Filters work?
When your water is underground in your well, it is usually clear in color, even though it may contain high levels of iron. This is known as ‘ferrous’ or clear water iron. Iron filters take this clear iron and transform it to rust or ferric iron in the process known as oxidation. These trapped particles are periodically and automatically backwashed out to drain, usually once or twice a week. Most iron filters remove both clear water iron and ferric iron (rust).
Signs that you have iron or manganese in your household’s water:
- Rust and black colored stains on sinks, toilets and showers
- Strong metallic taste
- Laundry that is nearly impossible to get clean
Iron and manganese sometimes occur in water together and are sometimes accompanied by a rotten egg or sulfur odor. Iron in water typically takes on three basic forms: ferrous iron, ferric iron and iron bacteria.
Water that is clear when drawn but changes to a yellow or rusty color upon standing is known as ferrous or clear water iron. This iron has not yet been exposed to oxygen and therefore has not “rusted” or oxidized. This iron is totally dissolved in water. This clear iron can easily pass through standard home store sediment filters, thwarting the best efforts of homeowners, then later change to a staining color on the surface of sinks, toilets or showers where air oxidizes it.
Ferric iron is sometimes known as red water iron because of its rusty red appearance when drawn. It is actually clear water iron, which has been oxidized, usually from dissolved oxygen or other factors in the water. This type of iron is not dissolved in the water but rather is suspended in solution.
Ferric iron can also be formed from ferrous iron simply by letting it stand for a while. This sometimes can be witnessed in toilet bowls. Homeowners are sometimes surprised to find that upon returning from vacation, the water in their toilets has turned color. This somewhat unpleasant example shows a transformation from ferrous to ferric iron due the addition of oxygen from the air.
Iron bacteria are actually living organisms, which feed on iron in water, iron pipes and fittings. They pose no health risk but can be very damaging to the plumbing system. These bacteria form a reddish-brown slime, which may clog pipes and fixtures. Occasionally this slime breaks loose causing spurts of extremely discolored water. Iron bacteria can be identified by reddish-brown or sometimes yellow, gelatinous formations on the surface of the water in toilet flush tanks or by slimy clumps of iron oozing from pipe leaks or corrosion. They can cause bad tastes and odors in the water supply.