Please critique my iron staining plan of attack


Gold Supporter
Jul 25, 2020
Atlanta, GA
Hi, everyone - I'm Kim. I'm here because pool stores have let us down too many times.

Our pool currently has an iron stain throughout the pool. I'm certain it's iron because the Iron Stain Remover that the pool store sold us worked, it's just that it came back (multiple times - the pool store gave us help on getting rid of the stain, just not keeping it away)

My husband said that if I can lick this iron staining problem, then I get to choose the restaurant for a dinner out, and in our family of 7, that's a big deal. :cool: My future engineer son and I are now in charge of the pool - with our analytical brains and this wonderful forum, I feel like we can do it!

Here are our results (we're new at this, so weird test results may be user error)

pH 7.5
FC 1 ppm (SWG has been switched off starting on Sunday to lower chlorine for AA treatment)
CC .5
TC 1.5
CH 350
TA 110
CYA 50

From reading tons of articles and posts on this website, here is my plan of attack -- please let me know if I'm off base, and if you don't mind, I'll post follow up tests to make sure that I'm still on track as we go.

1. Get my pH and TA down by adding 32 oz. of 31.45% Muriatic Acid
2. Once the ascorbic acid gets here (probably Wednesday or Thursday), check FC again, and if it's zero, then put filter on circulate and add 2.5 lbs of ascorbic acid
3. Add polyquat 60
4. circulate until stain is gone
5. Add two quarts of The Purple Stuff and put filter back on filter
6. After 24 hours, test, and then start to re-balance water, but keep pH between 7.0 and 7.2.
7. If I start to see stains come back, add 16 oz of The Purple Stuff.

I feel unsure about steps 6 and 7 and the ongoing maintenance of this. This stain just appeared this year, so I don't think it's our fill water. I suspect that it's the pool salt sold to us by the pool store that we switched to this year.

Also, I know that my CYA is low - should I raise that up now, or wait until after the AA treatment?

Thank you all!

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello and welcome to TFP! :wave: You have a pretty sound plan of attack there. Perhaps the only thing going against you is that it's almost August and it's HOT. So we know with that FC level as low as it is, you may already have excessive organics trying to grow, By the time you get to Weds or Thurs, you could have an algae mess on your hands. Let me ask you this .... are the stains so bad that you can't wait until Oct-Nov? Or just next spring maybe? The cooler water should be good to have.

But if you decide to do the AA now, I might even consider getting some Polyquat in there now (if it's not too late) because that low FC isn't going to protect you for long. Once algae sets-in, all bets are off and it's off to a SLAM Process to kill the algae.

You should also take a look at this thread for some outstanding results. The most ideal way to treat for iron is either a fresh water fill or by removing as much iron as possible. Hope that helps.



Gold Supporter
Jul 25, 2020
Atlanta, GA
For the polyfill technique, is the idea that I would put polyfill in my skimmer baskets after I do the AA and add sequestrant? And then check and rinse daily to get the iron out of the pool? Then I wouldn't need sequestrant anymore?

I've checked our county water quality report, and there is no mention of iron or ferrous anything. Please let me know if there is something else that I should be checking.

Just wanted to be sure, because I come home with a box of that stuff I'm gonna get some looks haha.


Jul 27, 2020
Santa Clarita, CA
Is the staining appearing in little spots or just a general stain? Our pool started having a small brown stain in one spot about 6" under the surface. Our local pro suggested draining some of the water and saturating the spot with muriatic acid. He said if the spot disappears it is an iron stain. If it comes back it means a piece of the ironwork is to near the surface and is rusting.


Gold Supporter
Jul 25, 2020
Atlanta, GA
It is the whole pool, but most significantly on the stairs.


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Well-known member
Aug 15, 2019
Danielsville, GA
Hello...looks like we are neighbors! We had the same sort of staining on our stairs, just not as dark of stain. After seeing that the staining did respond to a vitamin C tablet, decided to try vitamin C in a sock. Worked like a charm! A few days in the pool, and a few days of rubbing the sock on the stairs we were able to clean things right up. I have seen the stains return just a little but so much better than it was. Didn’t want to risk lowering the FC to try the AA treatment. Bought the tablets at grocery when they were BOGO. Took about two bottles. Best of luck!


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Gold Supporter
Jul 25, 2020
Atlanta, GA
Hi all, my FC is now zero and my pH is 7.2. I added a quart of polyquat 60 on Monday night.
My ascorbic acid now isn’t scheduled to arrive until tomorrow.

am I ok to wait until tomorrow to start the AA?

do I need to go get more polyquat 60 to add today?

shpuld I turn my SWG dial up a bit?

I know it would be easier to wait until the fall to do the AA treatment, but because the staining is so bad, we’d like to do it now.


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Gold Supporter
Jul 25, 2020
Atlanta, GA
Do you have a pool cover? That might help take some heat off of the pool.
No, we do not. AA, Purple Stuff, and more polyquat 60 are arriving tomorrow. I’m not above going back to Leslie’s to get more polyquat to add today if needed. How long does that stuff last?

thank you so much for your help!


Gold Supporter
Mar 21, 2016
Atlanta Ga
I just did one and the poly 60 kept my algae out so maybe it will hold on..
One thing is you will need a lot of Chlorine to recover, Vit C neutralizes CH so have 3 or 4 gallons of liquid ready to go.
The steps I used form here said keep PH around 7.2 and don't bring CH up too fast but it will take more then normal

I let mine circulate over night also..I decided I would rather battle any algae later and let the ascorbic acid do it's thing :)
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Bronze Supporter
Aug 15, 2017
I would start with a light dose of AA, you can always add more. The more you add the more chlorine needed to overcome.

The advice I was given here which worked for me in rebalancing the pool without restaining was to increase chlorine slowly. Slowly was defined as by 1ppm increments aiming for the bottom of your target range.Testing and adding every hour. Took about 3-4 additions till it started to hold, then continue to slowly bring it up.


Gold Supporter
Mar 21, 2016
Atlanta Ga
I have bad stains that came when the pool was drained and had been acid washed. Pretty sure the iron washed off the new Stone and down the sides. LOoked horrible but at the time I thought it was organic from leaves so kept filling it.
I used 10 pds in divided does and got 85% up but it took me 2 weeks of watching and adding liquid to get my CH to start holding.
I may do another treatment in the spring when the water is still cold.


Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-30 Plus

I just finished dealing with the same thing on a gemcoat pool. My stains were very similar to yours. AA started lifting the stains immediately, 90% lifted in just a couple hours. By morning next day the pool looked brand new. I used Pool Team Metal Magic but I think it's the same sequestrant. Don't be surprised if your pool looks fantastic then turns cloudy as the pH rises. Mine did that yesterday. Very, very cloudy, I could barely see the bottom. Cleared very quickly with a filter clean plus change of the Polyfil in the skimmer. By end of day it was much better. This morning it's perfect. My pool is about half your size so for your pool I would use 2x my addition amounts. Here's a couple things I learned that may help you:

  • It took 3 steps of MA addition to get my pH from 7.5 to below 7.2 and I actually overshot a little to 6,9.
  • I did .5 lb AA to start and then noticed my FC very quickly dropped from 2 to 0. I tried to put it mostly directly over the stains but it's such a small amount of powder for the whole pool you have to be sparing with it or you'll be out before you get 1/4 way around the pool. I wasn't sure how much AA I had consumed so I added .5 lb more. This worked fine.
  • Day 2 the pool actually sparkled just like brand new. But pH was still just 6.9. I added 65 oz 20 mule team Borax to raise it to 7.2 initially. I added 11 oz Polyquat 60 at this point.
  • Day 3 pH was at 7.5 (maybe complete mixing took a day). At this point I added sequestrant. One 32 oz bottle slowly around the edge of the pool just like the AA. After addition I added Polyfil to the skimmer. Late that day it appeared to be trapping tiny, tiny dark brown particles
  • Day 4 Pool looked great but a little cloudy late.
  • Day 5 So cloudy I barely saw the bottom. Filter pressure was up 30% by noon so I cleaned the filter cartridge and changed Polyfil. By day's end it was much clearer but still cloudy.
  • This morning the pool is perfect again. I'll change Polyfil and clean cartridge later today. Photo's are at sunrise this morning.

Good luck and I hope this is helpful.




Last edited:


Gold Supporter
Jul 25, 2020
Atlanta, GA
woo-hoo -- the AA arrived! The Assistant to the Pool Director put about 1.5 lbs in the pool after making a couple of wise cracks, and the filter on circulate, and the stain is already gone.

Purple Stuff and additional polyquat is due to arrive tomorrow. I plan to add a small maintenance dose of Polyquat 60, and then wait 24 hours, and then start to slowly rebalance the pool.

Thanks again for the continuing help!


Gold Supporter
Jul 25, 2020
Atlanta, GA
Morning everyone!

I'm at the point now in the AA process where the pool store let me down twice -- so this is the part I'm nervous about. If someone could just hold my hand through these next few steps, I would appreciate it!

Here's where I'm at:

Monday (7/27) - Added 32 oz of Polyquat. FC was 1.0 and pH was 7.5
Tuesday - Added 32 oz of 31.45% Muriatic Acid to lower pH. That evening FC was 0.0 and pH was 7.2
Wednesday - Added 2lbs ascorbic acid. Stain disappeared almost immediately throughout the whole pool. FC was 0, pH was 7.2,
Thursday - We added polyfil to the skimmer baskets. Daughter was relieved that she didn't have to sacrifice her stuffed animals as her brother threatened to do. FC was 0.0, pH was 7.2, TA was 100, and CYA was 30, so we added 5 lbs of dry stabilizer to raise CYA.
Friday -- Jacks Magic Purple Stuff finally arrived! Added 2.5 qts of purple stuff to the pool. polyfill had a slight stain by this evening, so we changed it out.

water is blue but very cloudy.

FC 0
CC 0
pH 7.1
TA 120
CH 275
CYA less than 20 -- we could still see the dot at 20

The next step would be to start to raise chlorine, correct? I'll dial up to 10% on my SWG and see how it goes.

I clearly have a CYA problem - should I go get more stabilizer and start adding that now as we raise the chlorine up?

As we are doing these tests to check for chlorine as we go, is the K-1000 sufficient, or should we do the full blown test with the powder?

I know that the AA treatment can lead to cloudy water, but I'm preparing myself that I may need to do a SLAM in 2 weeks to clear up the water.

Thanks, y'all.

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