I have this yellow mustard stain around my whole pool and down the walls. Could this be caused by Pool Perfect phos free? Is it copper caused? I checked with 2 local pool stores, both had no remedy, but one did day use 50/50 Muriatic acid on the vinyl, which did work but won't work on the walls. I need to remedy the wholee pool. I really don't want to put gallons of acid in a vinyl pool. Bleach didn't help, vinegar didn't help, vitamin C didn't work, but I think I did that wrong. Any help would be appreciated.
Can you solve this puzzle (Stains)
- Thread starter SunFunGuy
- Start date
- Jun 22, 2014
- 49,350
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Welcome! 
Best we start with a full set of water test results to best diagnose. Do you have a TF-Series test kit, or Taylor K-2006C?
Best we start with a full set of water test results to best diagnose. Do you have a TF-Series test kit, or Taylor K-2006C?