Stain - fibreglass - small orange spots - random - tried everything

[WantaSwim]

Good day
Fibreglass - chemicals are in range -
I have spots on stairs, in corners. Yellow / organge. I have tried everything
Vitamin C, muriatic acid,12% chlorine, pucks, Iron Out spray, Commet, sandpaper, vinegar, citric acid
Your Thoughts ?
See photos, hopefully they will show….
Thanks for any guidance

 

[Texas Splash]

I actually found some of those in my pool a while back and nothing seems to have worked yet either. Very odd. Only thing I can think of is perhaps some granular pesticide blew into the water after I spread it and cut the grass. Might be some type of mineral that is resistant to Vitamin C. But sanding didn't remove yours? That's odd. Perhaps the product making those stains penetrated the porous areas of the shell. You might try Jack's Stain ID Kit. Other than trying some pH Down granules (for copper based) in a thin sock, that's about the only other thing I can think of trying.

How old is your shell?

 

[Winger 03]

I pretty much have the same thing in my pool. Nothing seems to work - though I have not tried sanding or the stain ID kit. It started with 2 or 3, and now I seem to get a few more each year. My cleaner bag has several "rust" stains as well. My guess is something from the lawn, but I do not know for sure.

 

[1poolman1]

I pretty much have the same thing in my pool. Nothing seems to work - though I have not tried sanding or the stain ID kit. It started with 2 or 3, and now I seem to get a few more each year. My cleaner bag has several "rust" stains as well. My guess is something from the lawn, but I do not know for sure.

If you fertilize your lawn with a spreader, realize that pretty much all lawn-food product have some form of iron in them.

 

[WantaSwim]

Thanks for the reply’s
I did try the PH down - no luck
I also saw the small dots in the filter bag of the robot

In some case the fibreglass looks pitted

It looks like a very expensive issue that I hope will not continue or happen again

Thanks very much for replying