Imaginary iron in pool?

RainBH

Member
Jun 25, 2019
9
Benton, Illinois
Hello, everyone. I've been lurking around the forums for some time now, and while I've gathered a lot of good information, I'm still struggling with my pool this year (2nd year of owning it). I'm cursed with the iron staining problem, and I feel like the pool store is just milking my wallet.

My pool is 12,000 gallons, in-ground, sand filter, and filled with municipal water (no iron indicated in tests).
Test Results:
FC .99
TC 1.49
CC .5
pH 7.6
TA 51
CH 129
CYA 26
Copper/Iron/Manganese 0
Phosphates 3579

I followed the AA treatment guide on here twice, and the stains returned both times. It happens when I start to bring the chlorine back to the correct levels. I'm confused, because the pool store and my own tests are showing no iron in the water. They now have me pumping $55 bottles of phosphate remover into the pool, and it's going to be an extremely expensive treatment, if I keep that up. Though, it does collect a lot of rust colored material and drops it to the bottom of the pool to be vacuumed out.

Please help me! I've been at this since late April. I have a pretty basic understanding of pool chemistry, so forgive my ignorance.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
24,876
Northern NJ
Pool Size
35000
Surface
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Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Iron needs to be captured by a sequesterant like Jacks Magic or be filtered out with something like polyfill. Read Getting Rid of Iron and Stains in Your Pool - Trouble Free Pool

You must filter out the iron and remove it to get a lasting fix. Phosphate remover will not do anything for you.

We put no reliance on pool store testing and recommend you get either the TF-100 Test Kits or the Taylor k-2006C and do your own testing.

Is this what you followed for the AA treatment? Ascorbic Treatment to rid Pool of metal stains
 

RainBH

Member
Jun 25, 2019
9
Benton, Illinois
Thanks for responding. I've actually used Jacks Magic both times, as per the guide on here. I actually used the Taylor k2006 to test my water, which gave very close to the pool store's results. The fact that iron is reading zero is very confusing to me. Ascorbic acid makes it disappear instantly, so I know it's in there.
 

RainBH

Member
Jun 25, 2019
9
Benton, Illinois
Here's what they have me adding to it. Last time, it did remove a lot of staining, and it clumped it together at the bottom. I'm not really sure about it though, because I haven't seen it recommended anywhere on here.
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
24,876
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
The fact that iron is reading zero is very confusing to me.

The test for iron will only find iron that is in solution in the water. If the iron is bound to the sequesterant or AA then it will not read in the test. You are going through cycles of the iron moving from the sequesterant back into the water.

You either need to have continous use of the sequesterant to keep the iron locked up or filter the iron out with polyfill.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
24,876
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Put the poly fill in the skimmers and see what it catches.
 

RainBH

Member
Jun 25, 2019
9
Benton, Illinois
I've added the polyfill to the skimmer, but I was thinking. If the water is reading that there's no iron in the water, will it actually be able to filter it out? Does that mean it's just stuck onto the walls of the pool?
 

Shirker

Well-known member
Jul 2, 2014
616
Athens, GA - USA
If the iron is dissolved in the water then it will not be filtered out. But it also will not stain. Iron is only a problem when it comes out of solution. That is when you start to see stains but also when the polyfill has an opportunity to catch it. It is very possible to have a situation where slight changes in PH or chlorine levels will tip the iron one way or the other (in or out of solution). You will need to keep a close eye on your chemical levels (using a good test) and keep you water as balanced as possible.
 

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RainBH

Member
Jun 25, 2019
9
Benton, Illinois
That makes sense. Should I add ascorbic acid then raise the pH and chlorine levels again, to get that stage where the iron precipitates, but isn't stained onto the walls yet?

I added the Revive stuff (pictured above) last night, and it did its thing again, but the waste at the bottom of the pool is a white translucent color this time, whereas it was rust colored last time. I'm getting so confused and frustrated. ?
 

RainBH

Member
Jun 25, 2019
9
Benton, Illinois
Actually, yes. I've been meaning to get back on here to share my experience, but I kept forgetting to. Basically, the steps below are what I did to get the iron out of my pool.

Items needed:
Revive (32 oz.)
Citric acid or ascorbic acid
12.5% Chlorine

1. Let the chlorine drop to zero, or very close to zero, and get your pH around 7.0-7.2
2. Add 2 lbs. of citric acid per every 10,000 gal. (1 lb. ascorbic acid per 10,000 gal.)
3. Leave the filter running on recirculate overnight
4. After this stains have been lifted, add 1.5 gal. of chlorine per 10,000 gal. and allow to circulate for 10 minutes
5. Shut off the filter, wait 5 minutes, then begin adding the Revive (32 oz. per 10,000 gal.)
6. Wait 48 hours for the Revive to do its thing (rust colored clumps should appear at the bottom after about 24 hours)
7. Set filter to waste and vacuum out the rust colored stuff, then fill the pool with water, if needed
8. Wait another 24 hours, then vacuum to waste again
9. Shock and balance the pool as needed

IT'S VERY IMPORTANT TO ADD THE REVIVE QUICKLY AFTER ADDING THE CHLORINE!!!

Basically, what I believe is happening is the citric acid is pulling the iron off the walls, but it isn't putting it into the water in a state that can be filtered out. When the chlorine is added, the iron precipitates into the water, which gives a small window to get it out. If that window is missed, it will end up on the walls again. The Revive is used to clump the iron up and drop it to the bottom of the pool, during that small window.

This might not be the most cost or time efficient method, and I'm by no means an expert. I simply got tired of getting the runaround at the pool store, and being told "check your levels with a good kit" on here.

Note: This probably won't work on a pool that has iron in its source water. You'll need to add some sort of pre-pool filter to keep it out. There's several guides on how to do that, though.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,928
SW Indiana
Pool Size
21000
Surface
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Chlorine
Liquid Chlorine
Your reasoning isn’t crazy :) I’m not sure how revive works, but getting the iron into solution and making it precipitate is a valid method.

Do you live on the end of a water service area? Sometimes rust can accumulate in lines if there aren’t users beyond you on the main.
 

RainBH

Member
Jun 25, 2019
9
Benton, Illinois
No, we live in the middle of town. The pool store tests and my metal tester strips both indicated no iron in the source water.

My skimmer basket had started to rust and my skimmer box has some small spots, so that might be where it came from.

I ended up replacing the basket and spraying FlexSeal on it to hopefully prevent that much rust in the future.
 
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