Small Black dots in salt pool. Black algae?

[jeanne3434]

Thank you.
I noticed that the black dots do not smear at all. They remain intact. Does this mean that they are not algae? Thank you for your help. I will order the test kit.
Jeanne

[PoolDoc]

If you can't scrape anything off, at all, they are not black algae.

Try putting a vitamin C tablet on top of one of them. If it's copper oxide, it may lighten visibly.

Questions:

1. What sort of finish does the pool have?
2. Do you have a heater of any kind? What kind?
3. Have you used any sort of copper, ionic, or 'mineral' treatment or device?
4. Have you used any products -- algaecides, tablets, granules --that contain copper?