Help eliminating Iron from my hot tub


Well-known member
Aug 6, 2018
I'm a relatively new hot tub owner. I'm on my second refill after purchasing the hot tub about 6 months ago. One thing I've been having a difficulty combating is iron. I'm filling it up from a well that does not go through a water softener. I am using two EcoOne hose filters combined to help with the hard water. I also use an entire 16 oz bottle of Metal Gon when filling. It seems to work fine for about the first 6-8 weeks. Then after that I notice the filter starts to get really brown/orange. Then staining around the bottom circulation pump jet starts to show.

I believe the cause is iron in my water. The local pool store said the copper in my water was 0 but they couldn't test for iron. I know pool stores can be inaccurate, but I don't have a test kit for iron. Anything you would suggest to keep the staining away? The local pool store just suggested more sequesters like Metal Gon. I also have not been spraying down my filters with a hose enough. I try to do it once a week, but it really isn't that frequent. I'm wondering if just doing that will keep the staining off the shell of the hot tub.

Here are my readings:

  • FC: 5.5
  • CC: 0.5
  • pH: 7.5
  • CH: 130
  • TA: 70
  • CYA: 30
I should note that when I do my CH test, I have to add 5 drops of R-0012 first to avoid the fading endpoint. Even adding the R-0012 first still causes the water to shift to a purple before blue.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
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Well-known member
Apr 12, 2016
Kershaw, South Carolina
So I have the same problem, well water with lots of iron. I do have an iron filter in line between the well and the house that helps a lot but not completely, keeps my toilets pretty clean but after a while it makes my hot tub filter look like a coffee filter! tried one of those hose end filters and again it helps a little but that's it. I noticed that when I add water to my pool the water gets a greenish tint, but after the water goes through my sand filter for a day the water turns a beautiful blue again! So , this may not help you, but I now fill my hot tub with water from my pool! The sand filter does the job, a pleated filter will not. If you have a pool you could try that.. or rig a small sand filter up somehow. Just a thought.

EDIT TO ADD: A water softener wont eliminate it all either, and just because you have iron in your water does not mean you have hard water, hard water is high in calcium and such. My well water is naturally pretty soft but high in iron! Have your water tested before you put anything on there to fix a problem you might not have.
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