Hello All, So I've finally gotten the chemistry of my pool under control using BBB, thanks to you all. Now on to tackle a surface problem I'm having.
When I did a 75% drain on my pool to get rid of the calcium hardness and CYA, I also did some cleaning. I hit the block border with muriatic acid to take care of the calcium build up. And when the pool still had about 8 inches of water in the shallow end, I decided to take a scrub brush to an area that appeared to have some sort of stain. Well when I scrubbed it the surface gave way and turned into grit, revealing a dark material beneath it. Picture follows.
So two questions: What does my surface material look like (plaster, epoxy, etc.)? Second, what can I do about the erosion. Can it be patched? Can a matching patch be made or will I have to live with a noticeable blemish?
Facts: I've only owned the pool/home for 3 months. Don't have any history on it. Pool is about 5 years old.
There is also some staining that seems much more prominent when my FC gets low (outlined in the photo). Algae?
As always, thanks for the help. It feels so much better when you know what's going on instead of being at the mercy of whomever wants your money!