I DO!!!!!!!!!!
I thought it was from the sh*tty plaster job they did on my pool but now I think it is scale. The plasterers still did a terrible job around the corners, blobs of plaster not smooth and so on. My neighbor had a different PB but same plaster contractor and he complains ablout the plaster. I brushed and maintaned my water balance but my PH sky rocketed every day, I had to put acid every other day, I know I did not let it go more than three days so I am still puzzled how the scale got there.
I think it was because my pump was not installed till 4 days lafter plaster. I brushed three times a day but no where for the dust to go. ( I guess?). I suspect that they did not acid wash due to the way the plaster looked, I wasn't there to witness. I have small yellowish brown stains and I am picking up a stain kit tonight. In the meantime, I lowered my PH to 7.2 and have been brushing last three days and it looks a little better.