This pool was neglected while the house was unoccupied (foreclosure) and an investor brought it back to clear to sell the place. The pH was at 8 when I tested it. Is this calcium scale, or is the finish just messed up? The stained areas are definitely rougher than the unstained, but honestly, when you rub anywhere, the finish sorta flakes off in your fingers (like a course beach sand). There was a noticeable pile of this grit down by the main drain.