Inground vinyl liner metal stain help!

[Bodidley]

I have had nothing but problems with metal stains all year.I have used just about every product you can think of with limited success.Always had chlorine and ph at the levels as directed.Today I used some vanish by bosh and where it touched the liner and steps it got rid of it in minutes. looks like it would take 6 or 7 containers just to cover the deep end. I would appreciate any help you folks can offer!
Thanks for letting me join this forum!
Bodidley

[Teapot1]

Just buy ascorbic (citric) acid. Much lower cost than a pool shop. Make sure the chlorine is as low as possible. However that just changes the form from a staining version back into a non staining soluble version. To actually remove the metals requires a care process. A great filter media for removing metals is Dryden Aqua's AFM ng media.

[Bodidley]

Looks like more ascorbic acid !
Thanks

[Teapot1]

But you will still need to actually remove the metals otherwise when you add chlorine, an oxidising agent the metals will again become oxidised and plate out on the surface