All stains not gone after StainFree - AA treatment


May 19, 2009
23000 Gallon printed Liner.
30' round 1.5HP 22"SandFilter.
Untreated this winter due to Gustav.
Finally got water clear and correct but had what I first thought was algae problem that
I could brush off but now has a faint stain in perimeter about 60-70% surface coverage.

Free Chlorine was at 1.2
PH was at 8.3

Pool guy said wait 3 days and if FC was <1.0 I could begin Ascorbic Acid treatment.
It worked a little. About 70% stain area was cleaned. 1 large patch and a couple of
streaks remained. I had used 2 bottles StainFree (1.75 lbs each) initially. I then waited
1 day while circulating and it didn't clear up. Instead of putting any Metal Free in I bought
2 more bottles of Stain Free - which helped a little more and then I added 1 bottle of MetalFree.

If the stain remains today - what should I do?
Last night FreeChlorine = <.5 & PH ~7.0 (I think)

I'm $200 into stain removal and it's still there. The only other time this happened (Katrina) the
Stainfree worked like magic....



LifeTime Supporter
Apr 24, 2007
Ashland PA
Try keeping the ph at 7.0 to 7.2 and add more sequestering agent - try jack's magic, metal magic, sequasol, or some other metal "remover". Sometimes different sequestering agents work better at certain times. I don't know why, it just happens. Put the pump on recirculate overnight. See if the stain gets lighter. If there is not enough sequestering agent the metals may fall out of solution again and stain . If the sequestering agent doesn't get rid of all the stain you may need more ascorbic acid, or citric acid. Let me know how you do.