Our pool is in its third season. This year we're struggling with a yellowish band that has formed at the water line. The pool is an in-ground vinyl lined, 25,000 gal. with a sand filter. We have city water but suspect this may have formed as a result of the Super Algaecide I use; copper. I've tried a number of products to remove the stain to no avail, including:
- United Chemical Pool Stain Treat; didn't do much besides lower my ph
- PH lower in a sock; wetting and holding the material on the stain for several minutes. No change
- Chlorine in a sock; same as above with no change
- Mr. Clean Magic Eraser Pads; removed some of the stain, not all. Must be careful not to scrub too hard or it removes the print
I've attached a few pics. Looking for any suggestions.
- United Chemical Pool Stain Treat; didn't do much besides lower my ph
- PH lower in a sock; wetting and holding the material on the stain for several minutes. No change
- Chlorine in a sock; same as above with no change
- Mr. Clean Magic Eraser Pads; removed some of the stain, not all. Must be careful not to scrub too hard or it removes the print
I've attached a few pics. Looking for any suggestions.
It's true that if enough of the algaecide had been used over time, it could've increased your copper level to a point it's starting to find a place to stain. The only product it looks like you didn't try was Vitamin C tabs (crushed in a thin sock or nylon). Since the pH down didn't seem to have any effect on suspected copper (we usually try dry acid), it may not hurt to try the Vitamin C test (iron). But if the vitamin C has an opposite reaction (darker) that also confirms copper. While we typically discourage pool store testing and are huge advocates for proper home testing, this is one case where you might want to see what a free store test shows - for metals primarily. While you suspect copper, it would be good to confirm which battle you are fighting.