General Iron Filter Questions
Q. How do iron filters work?
A. 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).
The maximum level of iron recommended in water is 0.3 mg/L, which is the same as saying 0.3 Parts Per Million or PPM. When the level of iron in water exceeds the 0.3 mg/L limit, the water may appear a red, brown, or yellow color and stain laundry and fixtures.
The water may also have a metallic taste and an offensive odor. Water system piping and fixtures can become restricted or clogged, and appliances such as water heaters, dishwashers, and washing machines can become plugged with rust and sediment.
Q. Which is the best iron filter for my application?
A. This depends on your well water chemistry. The first step is finding out if your cold water has a sulfur odor in it, or if it is just the hot water and testing your water for iron, manganese, pH, hardness and total dissolved solids.
Click here for low-cost accurate water analysis.
For single-family homes, an iron filter that uses aeration combined with Pro-OX manganese dioxide filter media is recommended for most homeowners because it removes both types of iron, manganese, and sulfur odors.
Other types available are Greensand Iron Filters (which use potassium permanganate powder) and Birm Iron Filters (which work for some applications but do not remove sulfur odors or manganese).
In some cases, if the water has a very strong sulfur odor or has high levels of iron bacteria, a hydrogen peroxide or chlorine injection pump is recommended ahead of the Pro-OX iron filter.
Oxidizing Iron Filters
Iron filters oxidize the clear dissolved ferrous iron in water to an insoluble particle and trap the iron (rust) in the iron filter media. A periodic backwash cleans out the rust & flushes the filter media clean.
We recommend Pro-OX filter media as it is more powerful, removes higher levels of iron and lasts the longest. Other types of iron filter media are available including Birm, Greensand, MangOX™, Filox™, & Pyrolox™.
Oxidizing iron filters use either air, potassium permanganate, chlorine or ozone to aid the filter media in oxidizing the iron. ProOX media is a solid manganese dioxide media, whereas most iron filter media use a thin coating of manganese dioxide over some other type of filter media.
The solid manganese dioxide is the gold standard for iron filtration media, as the media lasts for many years, often 15 to 20 years and these systems can filter the water at a faster rate.
Q. Do these systems come in different sizes?
A. Yes. The size of the system is directly proportional to the flow rate of the water, in gallons per minute. The higher the flow, the larger the system required. Recommended backwash flow rates must be observed.
Q. Will there be a pressure drop through the system?
A. Properly sized, the system produces a very low-pressure drop at service flow rates, usually around 5 psi. Most people don’t see any pressure loss in their household piping.
Q. Can I route the backwash water to my septic tank?
A. Yes. The backwash water can be routed to the septic tank with no problem in almost all cases.
Q. Can’t I just use a water softener to remove iron?
A. Water softeners will remove dissolved clear water iron by a process known as ion-exchange. However, iron, manganese and/or hydrogen sulfide gas will eventually foul and ruin the ion-exchange resin.
If your water contains less than 2.0 ppm of iron and manganese combined and no sulfur odor, then you may be able to use a good quality water softener with a special type of resin cleaner in the brine tank.
The resin cleaner will help clean the resin when the softener is being regenerated with the salt water. We don’t recommend this approach, however, it is better to use an iron filter in front of the water softener for best results.
Q. What are “greensand” iron filters?
A. These filters use a specially formulated filter media made from a naturally mined form of glauconite greensand. The greensand filter media has a special coating of manganese oxide, which oxidizes iron, manganese, and iron in the water, upon contact with the filter media.
Greensand filters require a type of purple powder, potassium permanganate to regenerate and clean the greensand filter media.
Q. Can I get assistance in choosing an iron filter system for my application?
A. Yes! You should first have your water tested, and then contact our technical staff for help on selecting the best iron filter system for your application. Also, see our Custom Water System Design Questionnaire which makes it easy to help you select a system.
