I noticed this season three wrinkles in the liner along one wall of the pool. They're running parallel to each other and are fairly long, 3 or 4 feet. The liner appears to be seated firmly on top and the tile pattern hasn't changed. What I mean is, the pattern lines are still straight. This is the pool's 4th summer.
Is this something I need to be concerned about? Is it something I can fix myself or do I need to call a pool company?
Chems are great at pH=7.5, FC = 5, CC = 0, TA = 70, CYA = 30 and holding steady for more than a month now.
I would truly appreciate your thoughts on this.