Hello Trouble Free Pool!
So long story short, I left for vacation and came back to the green lagoon, decided it would be easier to drain and refill than fight the algae. So I drained it about 3/4 until the drains quit sucking water due to airlock in the pool pump. Left it for a couple weeks like that then finally finished draining with a sump pump.
After all the water was out, I was left with all these little specks all over the deep end where the water sat stagnant.
They look like someone took a fine point marker and made little dots everywhere, but they're slightly raised and they don't scrape off easily with a fingernail/wire brush. The pool has been empty for about a month now so I'm hoping whatever it is just got dried out and baked in the sun...
Is this black algae? Is it algae at all or some kind of mineral deposit in the old worn porous plaster?
I need to know because I'm planning on epoxying my pool in about a week..
Dropbox link to photos: https://www.dropbox.com/sh/e6eve9oib...C-RN8g7va?dl=0