Just bought a house, and I don't really understand how the water softening system is set up. Here's my best guess:

Water from the well is pretty hard, and very iron filled. It smells enough to smell it across the room. But: it does not smell like sulfur.

First the water goes through a water softener with a brine tank. Water at this point smells faintly of iron, but is much softer and still does not smell like sulfur.

After that it goes into another tank that looks like a water softener, (I can even force it to do a backwash) but has no company or product names on it, and no brine tank. I'm guessing that this is an iron filter. (Though I'm not sure why it would be after the water softener, because it seems like the softener is taking the bulk of the iron out.. And can't that foul the resin? I digress.) At this point the iron smell is completely gone, but now the water smells of sulfur.

It seems pretty clear what the problem is: sulfur contamination in the iron filter.. But from everything I can find online, that shouldn't be possible since most iron filters are sulfur filters.

Anyway, how far off am I from what my actual setup is, and how can I clean this tank?


1 Answer 1


It sounds like it's an activated carbon filter, which takes organics out of the water (like the sulphur smell), and that it needs to be rebedded (this needs to happen typically once every 3 to 5 years, depending on level of contamination). Once the activated carbon is 'used up', it actually becomes a good breeding ground for bacteria and is worse than completely ineffective. (Aside, this is the same reason that jug-style filters like Britta need to be replaced regularly -- and it's better to use nothing than an old one).

pile of activated carbon activated carbon pores

There is not really anything called an "iron filter". Softeners can low levels of iron out, and greensand filters can be used for higher levels, but a greensand filter will have a small tank attached with potassium permanganate (dark purple stuff) in it:

Potassium permanganate tank attached to greensand filter

  • In my opinion, calling a greensand filter an iron filter is accurate. advanced-water-systems.com/technical/faqs/faqs_greensand.html Sep 19, 2013 at 18:33
  • I definitely don't have the tank of potassium permanganate. So that would probably rule out greensand. It also seems like an activated carbon filter would have been the source of the very fine water bubbles we were getting before I shut it off. I also wouldn't be surprised if the system is over 5 years old and never rebedded, based on other things I've found in the house. Thanks! Sep 20, 2013 at 14:51
  • Update: Cycling the carbon filter cleared the smell from the water.. for about two days. Turns out, there's another small GE whole house sediment filter that got contaminated with the sulfur. Switched that and everything's good! Sep 23, 2013 at 16:26
  • The comment above about the carbon could be true however you should test your well water before it go through any filters to see exactly what is in it and you should open up that second tank and see what is in it many times after you soften your water the anode rod in your were here will put off a sulfur smell this will be in your hot water you remove the anode rod from your description it does not sound like your system is setup correctly if you do have an iron filterand youu are correct they usually remove sulfur as well as iron this filter may have a product in it called phylox this media o
    – user45195
    Nov 3, 2015 at 15:32

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