24' AGP, 54" - 13,300 Gallons at 47".
Hayward Swimpro Voyager Filter/2 Speed 2 HP Pump
Are the wrinkles towards the bottom of the wall down by the cove?
24' X 54" round AGP with Uni-Bead Portofino Liner - 25 Gauge, partially in-ground. Hayward Perflex EC-40 D.E. Filter System 1-HP Power-Flo Pump. Installed Spring 2014.
Looks like water behind the liner to me. Wrinkles are creases. Those look puffy, indicating water.
I'd bet you my bikini you'll never get TFP water from a pool store!
24' Sharkline Venture De Filter
I'm agreeing with Casey that looks like water. How high is the groundwater around your pool? Do you have dry wells or a drain system?
22k gallon IG pebblefina, Jandy 1.5 HP VS, Jandy CV Cartridge filter, Heliocol solar panels, Polaris 360 supply side cleaner, waterfall