1st season owning a pool. Pool itself is ~25 years old, I believe the pool is on its third liner. I've noticed that the blue pattern on the liner, specifically in the deep end, is relatively easily scratched off. I first noticed it because I've used the leaf rake the most frequently in this area, and inadvertently scraped some of the color off with the rake when getting debris off the bottom of the pool. I've checked other areas of the liner, and not all areas of the liner have this issue. Specifically seems to be the liner on the bottom of the pool (not so much sides or slopes), and the issue is worst in the deep end. I'll obviously be more careful with the rake from now on, but wanted to find out what may have caused the issue and what I should be doing to avoid making it worse on other areas of the liner. I've been following the TFP method (currently at CYA of 30, keeping FC between 2 and 6). I know previous pool owner followed pool store advice, didn't pay attention to CYA, used pucks and granular chlorine, blindly shocked once a week. Thanks!