We often get questions about iron filter media here at Clean Water Systems. It seems many people are overwhelmed by the breadth of options available when shopping for an iron filter, and with all sorts of tanks, valves, and filter media available, it’s not hard to see why. That’s why we wanted to take some time to explain the differences between some popular filter media, so that next time you are shopping for an iron filter you can make the right choice with confidence.
For starters, Filox, MangOX, and Pyrolox are all brand names for solid manganese dioxide filter media. The media is made from >80% pure manganese, and is collected and processed specifically for water treatment due to its purity. You can find solid manganese media of a much lower purity (usually less than 50%) in some other countries, which is why Pyrolox, Filox, and MangOX are generally seen as the gold standard in iron filter media.
Some people choose to forego solid manganese media in their filter and instead use coated manganese media like Greensand or Birm. These media use a light coating of manganese oxide over silica or other granular minerals to effectively filter iron from water.
Solid and coated manganese media are similarly effective, but solid media will last much longer. In fact, we’ve had reports of customers who are still using solid manganese media that they purchased as far back as 1990! Greensand, on the other hand, will last about 5 years before the manganese coating starts to wear off and the media requires changing. The trade-off is that solid manganese media is significantly more expensive than coated manganese media like Greensand, and significantly heavier.
Because the process of backwashing requires lifting and fluidizing the media bed from the bottom up, heavier media requires a higher backwash flow rate. Solid media weighs about 120-140 lbs per cubic foot, while Greensand weighs in at about 80 lbs per cubic foot. Greensand can thus be advantageous for users whose well pump’s flow rate is insufficient to backwash solid media.
Generally, we prefer solid manganese media such as Pyrolox or MangOX, because it lasts longer and is more powerful. It has somewhat stronger oxiding ability than coated media like Greensand, so the service flow rate through the filter tends to be higher.
However, for most home applications, either a solid media or Greensand filter will do just fine in removing iron from your water. We also recommend a chlorine feeder before an iron filter to oxidize iron, making it easier to filter, and kill any iron bacteria that may be present.
We hope this post makes choosing iron filter media a little less overwhelming. It really is up to you if you want to use solid or coated media. Just keep this info in mind the next time you find yourself in the market for an iron filter and we are sure you’ll make the best choice for your application.