Plaster discoloration

[mriddell]

New pool here. Fill dirt was substantially red with a fair amt of clay. Seeing some staining that I can’t seem to remove. Tried a wire brush without much success. Any thoughts?

 

[mknauss]

Try the tests shown in Stains in Your Pool

 

[mriddell]

Thanks. Vitamin C it is.

 

[mriddell]

Vitamin C appears definitive to me. Checked the infill water with high dose chlorine. Remains clear with no discoloration. Vit C tabs on two spots with almost clearing at 4-5 min.
Think this is related to dirt brought to the site that is very red, probably a red clay mix. That surrounded the pool until recently and we did have some blowing into the pool. I understand that red clay is very high in iron content. Uggh.