One of two things has happened over time in my pool. Either the pool has shrunk, or the liner has grown. My bet is on liner growth.
When installed the liner fit like a glove, perhaps even too small. I heard the installer's talking between each other and it sounded like trouble, they also called their boss and got some over the phone instructions which sounded like "go ahead and install it". All this was spoken in Spanish so i may have misunderstood. The following summer wrinkles started showing up. Long story short now i have significant extra pool liner on my full length steps, the "shallow" end floor, and along some parts of the wall.
If my liner was stretched to remove all wrinkles on the steps, i would estimate there to be an extra 4-6" of liner.
Pool builder finally came out again and admitted things aren't right. He's going to research with the 3 manufactures he uses and set up a time to have the rep come out and look for himself.
Pool builder said he's seen 1 other case of this, shortly after my install, it was an indoor pool with an autocover, and pool was around 100 degrees a lot of the time.
My pool has been through periods of time where it is 96, and if left uncirculated in the day on sunny days the top 12" off water can easily exceed 100 degrees.
What are all of your theories as to how this could happen? Pool builder pointed out to me that the floor of the liner appears to be a different shade of liner than the walls.
I've been asked to figure out how hot the superheated layer of water can get, so today i'll measure it and have a number.