First time doing acid treatment to remove stains. Questions!

TigerGalLE

Member
Jun 10, 2020
22
Upstate South Carolina
Pool Size
18000
Surface
Fiberglass
Chlorine
Salt Water Generator
Hey there. I have A 18,000 gallon fiberglass pool. I have some staining that I have determined to be iron staining. A test of ascorbic acid lifted the stains. I have purchased 4 lbs of citric acid and a bad of jack’s magic the filter fiber stuff.

It has taken me a long time to get my chlorine down. It is now down to 2.5 so I am anticipating performing my acid treatment in the next few days.

I have a sand filter and my main questions are about the filter. At what point do I add The Filter Fiber stuff and what do i need to do to protect my filter from the acid or metals?

I’m not sure the order I put my pump on recirculate vs the regular setting vs backwash.
I’m new to this!! Eek

Laurie
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,153
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
The instructions on the stain remover I bought says “ it is vital to add a pulp based filter aid to cartridge and sand filters.”
It is not something that we recommend using.

We also don't recommend using citrus acid instead of ascorbic acid.

The only thing we recommend adding to a sand filter is maybe a cup of pool grade DE to improve the filtration.

 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,153
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I have read the ascorbic acid link. I’m thinking now that circulate and recirculate are the same thing. Is that correct?
No. That was a typo and I fixed it to RECIRCULATE.

CIRCULATE or FILTER runs the water through the filter.

RECIRCULATE bypasses the filter.

 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,153
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I have read the ascorbic acid link. I’m thinking now that circulate and recirculate are the same thing. Is that correct?
No. That was a typo and I fixed it to RECIRCULATE.

Thanks for asking about it and pointing it out.
 
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TigerGalLE

Member
Jun 10, 2020
22
Upstate South Carolina
Pool Size
18000
Surface
Fiberglass
Chlorine
Salt Water Generator
So I need to get a sequestering agent then?
So set to recirculate while acid is added and then add the sequestering agent before putting back to filter?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
22,153
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
So I need to get a sequestering agent then?
So set to recirculate while acid is added and then add the sequestering agent before putting back to filter?
Yes & yes.

The sequestering agent keeps the iron, that the ascorbic acid lifts off the surface, in suspension so the iron does not redeposit on pool surfaces and can be filtered or drained out of the pool.

Do you know how the iron got into your pool water? Do you have iron in your fill water?

 

TigerGalLE

Member
Jun 10, 2020
22
Upstate South Carolina
Pool Size
18000
Surface
Fiberglass
Chlorine
Salt Water Generator
I am not sure. We planted sod and did fertilize it some. Also what is strange is today the staining isn’t as bad. I’m not sure if the cooler temps come into play or not. My water temp today was 57. My salt is 3600.
I haven’t started any treatment. Maybe the lower chlorine level has helped lift the stains? Originally I thought the stains were organic due to leaves and debris so I SLAM’d my pool. That didn’t help so I began to research more. The vitamin C tablet lifts the stain.
I have city water.