OK to have water behind the Vinyl pool liner?

[dualcool]

Aloha everyone, I am currently having a problem with the contractor who installed my vinyl liner. When the job was completed (pool full of water), I noticed that the vinyl liner was not locked into the corners (90 degree corners) and the liner fit like a round ball sitting in the corner. The gap that was created in the corners allowed for water to get in behind the liner. My contractor said "don't worry about it, a little water behind the liner won't hurt anything." He sent his workers out (on four different occasions) to 'stretch' the corners so they would fit. We poured hot water on the liner and stretched it as much as we could but the liner could not be stretched enough (still a 1x2 inch gap). Maratta said "oh they don't make liners for square pools anymore" and "liners don't like square pools." He said all kinds of things but bottomline, the liner does not fit. See the video at https://www.youtube.com/watch?v=sWlw-tIQOkc .
His own worker told me that he was afraid if we tried to stretch the liner anymore, it would tear the liner. Of course Maratta refuses to fix the liner (new bigger liner that fits with square corners) but offered to fix the problem if I paid him an additional $3800 (coincidentally the cost of a new liner). I have contracted a new company to fix the liner and have taken the matter to small claims court.

My questions to the Forum:

Is it ever "ok" to have water behind the liner?

Is it Ok to have 1-2 inch gaps in the corners where water can get behind?
Do they still make liners for square pools (90 degree corners)?

Is it recommended and/or OK to stretch the liner with boiling water?

Ok to have rounded corners in a square pool (air pockets in corners)?

I thank anyone and everyone for assistance in resolving my questions.
Aloha, dualcool out

 

[psihiart]

The forum is kind of dead so I chime in. I'm not a pro but having water behind liner does not seem right. My pool has rounded corners and there is no gap, my liner bead sits tight in a slot. There is some space however behind those corners but it has no water in it, just air.

 

[MarianParoo]

My liner shifted upon installation and some vertical and floor corners are off like yours. It has been fine. However, I am more worried about the coping areas where there are big gaps.

 

[crashxx]

I don't know about the water part, but I just finished installing my pool and had a similar deal with the corners. Pool kit was for 6" corners but the copping that come with the automatic cover had 90 degree corners. It was about 95 outside the day we put the liner in. We had to stretch it quite a bit and it was pretty tough to get the bead shoved into the corners. The kit came with foam corner pieces to fill the void in the corners.

 

[swimcmp]

Water behind the liner isn't ideal. Sometimes groundwater levels will put water there. Square corners with vinyl in our 30 plus years has never worked well as the vinyl won't seat into the corners

 

[crashxx]

What is the best way to handle a pool with square corners? We have square corners and I've put foam corners behind the liner, but the bead was tough to get in. Any recommendations for when it is time for a liner change?