Some yellow staining

[Mrjohn2you]

Hello, I drained the pool here in Phoenix AZ after I neglected the pool for too long. I noticed some yellow staining on the side and some not pictured dark staining at the bottom. Any suggestions? I read some posts that warned against acid washes. Thoughts?

 

[Mrjohn2you]

I power washed the pool and it did not remove the yellowing or the black grey stained bottom.

 

[Bperry]

I power washed the pool and it did not remove the yellowing or the black grey stained bottom.

It may be metal staining (maybe iron). There are some kits made by jacks magic to identity and treat them. Be very careful with a pressure washer, it can damage the plaster.