Hi, I'm new to the forum so not sure where to post this, I just drained my pool to clean, and our pool has had these blue stains on the walls for some time, I am wondering what these are and how best to remove/clean them while I haven't refilled my pool yet. I've shown these pictures to our local pool store and they said its calcium deposits.
I've looked around but not sure how to remove these, does muriatic acid help to remove these stains? or is there a better method? Any help would be appreciated