Brown Stains In Pool Quickly Getting Worse

[tpreva]

Hey All! New to the forums but have been lurking for a few months due to a new to me pool.

Opened it 2 weeks ago and it has been a bit of a nightmare but finally felt like I was getting somewhere when brown spots started appearing everywhere. Think it is Iron but looking to get some help.

Current reading in pictures with high FC due to slam process.


Pool Backstory-
Bought house with a fiberglass pool a few months back. Opened the pool to a swamp that we quickly cleaned, but after testing the pool showed mostly 0s across the board with Taylor liquid kits. Was confused but after multiple times testing found out there was almost no salt, FC, or CYA. Brought all 3 up to level over the last weeks and the water cleared up but now the bottom of the pool is speckled with brown spots. Not sure of what to do as they will not come off with scrubbing and only get worse every day.

 

[JJ_Tex]

Did you fertilize recently by chance? It does look like Iron to me as well, but check out this article especially the Vitamin C test to test for Iron stains.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

 

[tpreva]

Did you fertilize recently by chance? It does look like Iron to me as well, but check out this article especially the Vitamin C test to test for Iron stains.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

No fertilizer in the last few months while it was closed. Brown spots started a day or so after I brought chlorine and a salt up from 0.

Talked to a neighbor and they said previous owner may have used an angle grinder on the grout lines? Wonder if that could be the cause.
Going to test for iron stains and then look into treating with citric acid.

 

[tpreva]

I lowered the chlorine using using sodium thiosulfate and tried some spot treatment with citric acid and it did not seem to work. Also tried using some liquid chlorine on stains but that also had no effect. Any ideas on the next steps to identify the stains?