Liner Tight on one Side
I installed a new unibead liner as a J-hook/V-bead for a 27' pool with 54" wall. During installation we started at one side hanging approximately 8' at a time, and alternated hanging in these increments in clockwise and counter-clockwise directions.
It installed relatively easily, only getting tight once we got to the last two sections of the wall. Once completely hung I noticed the last side we hung appeared to have air beneath it as it was pulled out and not lying flat against the wall like the first side we did.
I could tell there was more slack on the other side as well, however, I could easily push in the tight, airy side with my hand and touch the wall. I tried using a shop vac to remove the air, but this did not appear to be helping any and since I could push it in and touch the wall I figured the water would automatically fix the problem.
We now have only about 12" of water in the pool and I am concerned this may not fix itself - the side with more slack is lying nicely against the wall and the pre-formed foam cove, but the tight side is not and it has become tighter to where I cannot push it in and feel the cove at the bottom, although I can still push it in higher up and touch the wall, but with more effort now.
Before adding water I didn't think this was a big deal since I could easily push the liner in
with my hand or flat broom even at the bottom and feel the cove. Do I need to drain it down to almost nothing and try to pull a little extra slack to this side or will the water fix it once it gets higher?
It does sound like the liner is slightly off center. It happens very easily when the first half or so gets installed into the groove fairly loosely and the last portion gets pulled tight to make it all fit. The best thing would have been to pull it all out and re-install it with even pulling all the way around. Many times the first time is just a trial run. The second time you would have pulled tighter in the first half knowing you needed more liner on the second half.
When the sides are hung with even tension it is much easier to get the bottom centered perfectly. The only real fix would be to take all the water out and start over resetting the sides.
This is probably not necessary since you have gone this far as long as you can finish filling with the tight side in direct sunlight. The sun should warm the liner and it should easily finish filling and stretching without any problem.
What sounds like may have happened is you lost your sunlight. The liner was pushing to the wall easily and then you lost your sun and it stiffened up. The cure for that is to shut the water off as soon as the sun is off the liner. Start it up again the next day.