Post return line repairs: Small spots on liner

[PoolDoc]

Bits of steel will absolutely stain a liner. Usually the stains will be orange, not black, but black is possible. If you suspect iron from that source, Iron Out offers a better test.

Buy a bottle of Iron Out (detergent section of Walmart, etc) and put 1/2 cup in a snack bag. Open the bag against a stained area, so the Iron Out gets wet, but is not washed away. Again, 5 minutes of contact should be sufficient to produce visible change.

Test grit with the snack baggie method, but use sodium bisulfate (dry acid or pH Minus). Wear plastic gloves.

[nalesean]

I'm still working on this.

I verified the vitamin C test didn't work.

I have purchased the Iron out, but haven't had time to apply it as instructed.

Will update after that.

Thanks!

[PoolDoc]

OK.

I just reread the thread -- it's possible for concrete to fall through the water and stick tightly to a liner. But, it won't usually be black. Just thought I should mention that.