Splotchy liner question

[ned8377]

I've been treating for iron stains all summer and I am currently back at the point where stains had come back. I'm keeping PH at 7.1 and chlorine as low as possible. I'm now getting areas of the pool where the stain is lifting. Instead of the whole thing lifting gradually it is just specific areas or spots where the liner looks normal or more blue. Anyone experienced this or know what the cause could be?

 

[Swampwoman]

When did the splotches appear? Eg suddenly or gradually...
Did something, like dry acid, sit on the floor?
When you treated with AA, it didn't sit on the floor, did it?

Have you had a chance to look at the splotches close up? Eg. Is there still pattern print on them, as in the original liner condition, or does your liner have a blue backing, and is the print actually eroded?

My liner was changed at 15 years (last year) and toward the end the deep end flat floor and shallow end (but not the slope) had the liner pattern eroded to the backer vinyl...but your liner isn't that old, is it?

 

[ned8377]

Thanks for your reply Swampwoman. The splotches appeared gradually. I use Muriatic mixed in water and then throw that in the pool. AA did not sit and if it had it would have turned the liner or made a splotch instantly. The liner looks like new where the splotches are as if I pored AA on that area. Actually, this has happened before but not to this extent. After putting AA in the pool, the entire liner would look brand new and the splotch would disappear. This has occurred in about a months time of keeping the PH and chlorine low. I did, however, slam the pool about a month ago and have let the chlorine drop but have kept the PH low throughout. About two weeks ago I cleaned the white plastic on the skimmers, lights and jets with a sock filled with Vit C tablets. They are still just as white as they were two weeks ago. I'm wondering if all of the iron has now come out of solution and there is none left to stain anything and also wondering if the low PH is helping to lift the stain?