One customer recently reported that his Greensand filter media was not lasting as long as it should, and required a lot of potassium permanganate to keep up regular operation. He also mentioned that he was experiencing acidic water along with iron and odors. These problems are not unrelated.
Iron is often found in acidic groundwater because the acid dissolves it into the water. The water may appear clear but will turn rusty when exposed to air.
In some cases, a water softener with fine mesh resin will remove the iron, though this water can be harmful to pipes and fixtures since it is both acidic and devoid of any buffering hardness minerals. However, a water softener alone will not remove odor.
A more thorough approach would be to use chlorine injection followed by a contact tank, then a calcite filter to neutralize the water's pH, and finally a Pro-OX or a greensand filter.
The chlorine will kill odor-causing bacteria and bring the iron out of solution, making it into solid, filterable particles, and the contact tank will provide enough time for these processes to occur.
The contact tank would then be followed by a calcite neutralizer, which uses calcite (crushed limestone) to react with the dissolved acid in the water and prevent corrosion. This would be followed by your Greensand filter to remove the iron and manganese. No potassium permanganate is required.
This way, the water is already disinfected and neutralized by the time it reaches the Greensand media. Treating your water before filtration will preserve your filter media, saving you money and effort on maintenance and replacement media.
We recommend a chlorinator, along with a contact tank. Optionally, you could include a carbon backwash filter after the Greensand filter to remove any residual chlorine in your water. The result will be clean, fresh, odor-free, non-corrosive, iron-free water throughout your home. See the diagram below for an idea of how these systems might be installed:
For more info, see our guide to iron and odor on our website, and browse our chlorinators, Greensand filters, and more in our online store. And don't forget, you can send any questions or comments to [email protected] or our Facebook page.