Question for you:
I have high iron. I put in a new system,along with the air injection tank as told by you with the air injection valve. I had emailed you a few weeks ago about still having an iron problem, you had told me to backwash more I have, I still have the same problem. my old system i didn't have this problem. I asked last time is there something more I should be adding to my mix tank?
Birm is very sensitive to low pH. A pH less than 7 degrades the Birm media, and can wear off the thin coating of manganese dioxide. At that point, it can filter out sediment, but will not remove dissolved iron from water.
It is hard to say what is happening in your iron filter, but it is possible that the Birm has failed and needs replacing. From our experience with hundreds of Birm iron filters, Birm lasts about 3 to 5 years, and often needs replacing, if it is older than 5 years.
Generally we recommend a neutralizer tank, ahead of a Birm iron filter, if the pH is less than 6.5. If the pH is slightly acidic, in the range of 6.5 to 6.9, sometimes a Birm blend (where there is calcite and Birm in the same filter tank) can work fine. One problem is, calcite is heavier than Birm, so it sinks to the bottom. The acid water comes in the top of the tank through the Birm, and flows down to the calcite, which is on the bottom. However, we do have many customers using the blend of calcite and Birm, since it saves money and space, but it is more difficult and less effective, when the pH is less than 6.
Another problem is, when the Birm-Calcite blend media is new, there may be enough calcite to neutralize the pH. However after 3 months have passed, the calcite is depleted and needs more added. At this point, the Birm can be damaged.
Our air-injector iron filter is called the Terminator, and you can find the replacement media here:
http://www.cleanwaterstore.com/filter-media-terminator.html#item=M1001180&tab=tab1
The Terminator Aqua Blend combines Filter Ag, Birm, Calcite and Corosex and is the standard media in our Terminator Plus Systems.
In conclusion, for Birm to work, it needs air injection plus a neutral pH, and regular backwashing. If the pH is neutral, and the air injection is working, and the Birm is less than 3 to 5 years old, then there may some other problem, such as internal bypassing or channeling around the filter media. This can happen if the calcite partially solidifies, and forms a block or chunk of calcite, and causes water to pass around the media. This would be apparent if you dumped out the filter media and found large balls or hunks of filter media inside the filter.
Here is a schematic diagram of how the Neutralizer with the Birm Filter should be set up:
