Recurring Iron Stain -- Looking for permanent solution

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S

SpykeYs

Well-known member
May 29, 2017
57
Canada
Pool Size
30000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-3)
Hi,

I recently (3 years ago) bought a new house with a 16x25 fiberglass pool (10 000 gallons) and I am having recurring Iron Stains issue which comes back at least once or twice every season. It covers the entire submerged fiberglass which becomes yellowish.

Before I start my acid ascorbic treatment:

FC: 0 (I did let it go to for the ascorbic treatment, previously was 4-6)
CH: 400
TA: 80
PH: 7.2
CYA: 50

I followed the directions as per the following link: Ascorbic Acid Treatment - Further Reading

Filter on recirculate, about 1 pound of ascorbic acid, add enough sequestering agent, etc.

Within minutes, all stains are gone and submerged fiberglass is pristine white... YAY! After 24-48 hours, I balance water again with PH between 6.8 and 7.2 and start pouring liquid chlorine VERY SLOW until all of it is eaten by the ascorbic acid... After my first poured gallon of liquid chlorine, I slowly saw a few stains come back... i continued to pour liquid chlorine very slow (half a gallon and then wait 30 minutes and check for FC... Result is always 0... continue to pour.... but after 3-4 gallons, FC was still 0 but ALL stains are back covering the entire pool..

I am getting very discouraged and I do not know what to do next.. I live in the city, I don't believe water has that much iron in it. I have a 2019 Hayward heat pump and a very old pool pump that I believe is rusted.. I had to get it repaired two years ago and I remember it was pretty rusty.. Could my water pump be the cultpit ?

I just do not know what to do anymore and before I start the process again, I was hoping you fine folks can provide some guidance on how to permanently resolve my issue.

If you are still reading, thank you VERY VERY much!

Peter
 
What kind and how much did you add? and how long did it mix into your water before starting your AA treatment?
 
I'm confused as heck. Pool looks like this morning..... i only added chlorine to bring FC back after ascorbic treatment...

Where to go from here ?
 

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You iron level must be through the roof. The AA was nice but short-lived because you were not able to exchange the water, so the iron never left. While that pool is ice tea brown, you need to filter it like crazy through polyfill. See the example below. This is the perfect time to mechanically remove as much iron as possible. Only after you have done that as much as possible, should you then go back to the AA/sequestrant route.

From brown to 😍😍. Thank you polyfil!

We filled our pool from our well. We knew the risks and knew we would have a battle when the water was 12" deep as it looked green from the metals. Our fears were confirmed when we added chlorine and the water turned brown almost immediately. Enter 5 gallon polyfil filter. It worked...
www.troublefreepool.com www.troublefreepool.com
 
Filter, filter, filter with polyfill. Any way you can. The more the better.

full
 
I'm more interested in the fixing the problem long term. Where in the heck is this iron coming from. As mentioned above, my pool pump is pretty old and is pretty rusted from the outside.

After AA and I did backflash multiple times. I'm just exhausted and want to fix the problem permanently as doing an ascorbic treatment 2-3 times a year does not make any sense.

Any guidance is more than appreciated.
 
SpykeYs said:
Where in the heck is this iron coming from.
Click to expand...
That's something you'll have to investigate from your end. Do you have steel/iron plumbing? Have you obtained local water history reports? Here in the US we go to our local country annual water reports. Are you on a well? It's one of those sources. Once you ID the true source of the iron, then you can begin to eliminate the iron from your pool. Since you have a FG pool, you can't simply dump it all after an AA, so continuous filtering with polyfill will be something you will have to consider, followed by sequestrant use.

Also important is your water chemistry which will impact the iron. Your Poolmath logs are blank so we have no idea of your chemistry. You're welcome tp post some test results if you like.
 
I don't have steel/iron plumbing but as mentioned but pool pump is pretty rusted. I'm tempted to say this is the culpit but it's an expensive replacement if it's not it. I'm confident it's not the city water.
 

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Hi everyone,

My pool water is back to being clear but stains are back everywhere, looks like I wasted lots of efforts and money to get back to the exact same result and I take full responsibility as definitely I did miss a step somewhere. What step did I do wrong is the question I have and how do I move forward now.

I'm tempted to get the ascorbic acid treatment going again and then change water. I only have about 10 000 gallons so I should be able to change water fairly easily. Thoughts ?
 
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SpykeYs said:
I'm tempted to get the ascorbic acid treatment going again and then change water. I only have about 10 000 gallons so I should be able to change water fairly easily. Thoughts ?
Click to expand...
If you can be sure to get fresh non-iron water for the refill, that may be your best solution.
 
Texas Splash said:
If you can be sure to get fresh non-iron water for the refill, that may be your best solution.
Click to expand...
After the ascorbic treatment, do I need sequestrant before changing water ? How soon after I add sequestrant can I start changing pool water. Thanks
 
SpykeYs said:
After the ascorbic treatment, do I need sequestrant before changing water ? How soon after I add sequestrant can I start changing pool water. Thanks
Click to expand...
Not needed if you time it right. As soon as the stains are lifted, dump the water (if you can) right away. Then refill and balance the new water accordingly. Hopefully the new water will be relatively iron free.
 
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Texas Splash said:
Not needed if you time it right. As soon as the stains are lifted, dump the water (if you can) right away. Then refill and balance the new water accordingly. Hopefully the new water will be relatively iron free.
Click to expand...
Thank you Texas Splash, you have been very helpful. I think I will do the following:

1. Bring PH between 6.8 and 7.2
2. Bring FC to 0
3. Add Algaicide
4. Add 1-2 pounds of ascorbic acid
5. As soon stains are gone, empty 80-90% of water and replace with new water
6. Balance new water


How does that sound for a plan ? My big question is what about next.. I know Iron is not coming from city water as I did review the latest water analysis available on their website and they contain absolutely no Iron. I need to find the source...
 
Texas Splash said:
Your plan sounds good. As to the source of the iron, that's the real question. As a test, you might try filling a bucket with house water then add a half cup of clorine just to see if it changes.
Click to expand...
I started my new AA treatment today at around 5 PM.... all stains are gone....

My goal is to replace ~75% of water tomorrow.

With 75% of water replaced, I assume most of the ascorbic acid will also be gone and I should be able to get FC to hold most quicker than if I would have not changed the water correct ?

What strategy should I employ once water has been replaced ?
 
SpykeYs said:
With 75% of water replaced, I assume most of the ascorbic acid will also be gone and I should be able to get FC to hold most quicker than if I would have not changed the water correct ?

What strategy should I employ once water has been replaced ?
Click to expand...
The transition from AA to chlorine should happen sooner. It will be important to ensure you have adequate CYA to help buffer the strength of the chlorine as you add it slowly in an effort to build FC and remove the last of the AA. It will be interesting to see how well your water responds now that you have exchanged a good amount of water. Let us know how it goes. Good luck!
 
Texas Splash said:
The transition from AA to chlorine should happen sooner. It will be important to ensure you have adequate CYA to help buffer the strength of the chlorine as you add it slowly in an effort to build FC and remove the last of the AA. It will be interesting to see how well your water responds now that you have exchanged a good amount of water. Let us know how it goes. Good luck!
Click to expand...
Can you define adding chlorine slowly... what should be the plan here ?

Half a gallon every 2 hours until it holds ?
 
SpykeYs said:
Can you define adding chlorine slowly... what should be the plan here ?

Half a gallon every 2 hours until it holds ?
Click to expand...
This is something you'll have to gauge as each pool and AA transition is a bit different. Once you get the pH back to a safe level, you'll add (for example) 1-2 ppm worth of chlorine and watch to see if staining tries to return. At the same time, you'll test the FC often since you can expect the residual AA to use some of the chlorine. At some point, as you add fresh chlorine, it should consume the residual AA and begin to hold. Your FC may also be fighting the sun's UV, so it's all a balancing act. You'll have to babysit the pool today as you add chlorine & re-test to see if it's holding. At the same time, keeping your fingers crossed the stains don't try to come back.

Ascorbic Acid Treatment - Further Reading

www.troublefreepool.com www.troublefreepool.com
 

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