Blue spots in white plaster

[Mirage21]

I have been noticing some blue (baby blue) spots in my white plaster. Can't brush them out. I don't know if it's my copper plumbing (the return/suction valves at the filter are copper, but a lot of the piping has been replaced with PVC, especially throughout the pool, return jets, etc.). Plaster is about 2 months old. I know the plaster company has used HASA stain out after the water was filled and recommends a bottle every 6 months.


Also, I have two brown spots that i cannot rub out with a stain eraser. Any recommendations on what to do next?

 

[Richard320]

Get some Vitamin C tablets and set them on the spot for a while. See if they lift. If they do, it's metal. Even a broken-off nail head that took a fly into the pool can leave a rust spot in as little as two days. Ask me how I know.

The blue spots? I haven't a clue. Can you post a picture?

 

[Mirage21]

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[onBalance]

Any update on the spots? If the treatment suggested above didn't work, you could try wet&dry sandpaper and see if they can be removed.