I have some sort of foam bottom on my AGP, and the seams are coming apart. I installed a new liner in September 2009, and re-taped all the seams at that time. Even so, the seams are coming apart and leaving deep grooves in the floor. In addition, the bottom is not smooth, but has a number of "hills and valleys" in it. The grooves are deep enough that in a few areas it is difficult to vacuum up the dirt that collects there. It's getting to the point where it really annoys me. (DW thinks it's fine, but I hate even looking at the bottom of my pool these days.)
The current bottom is gravel (I guess I'd call it a gravel chip). This is covered by a one-piece sheet of heavy plastic. I'd estimate the thickness as about twice as thick as that of a bleach jug. On top of that is a foam with lots of seams held together with duct tape. That foam seems to be shrinking. When I replaced the liner last, the foam was just barely big enough and in a few places barely reached the cove. Now in those places I can feel the edge of the foam, and the grooves are getting wider and deeper.
I'd like to pull the liner up, smooth the gravel substrate, and replace the foam with something seamless like a Gorrilla pad. I've been told that I can pull up and reinstall a 2 year old liner as long as I leave the skimmer and the return mounted so that those holes don't shift. It seems to make sense, and the liner still seems flexible enough that I might get away with it. The pH holds around 7.3-7.4 most of the time, and has not gotten out of that range for more than a few hours at a time (when running the fountain, for example.)
Does anyone have any experience with pulling up and reinstalling a liner of this age? Any thoughts on replacing the bottom? I'd really hate to do this and wind up having to replace the liner also. (DW would NOT find any humor in that!)