I have only done this one time. I branch fell from a tree in a wind storm from about 30 feet up. Went through the winter cover and through the liner in the deep end of the pools. It was stuck there when we opened the pool in the spring. The branch was about the size of a Baseball bat. I had prepared a zip lock back with play sand and also had a patch already cut. When ready, I removed the branch, placed the ziplock bag under the liner in the hole and then proceeded to patch the hole with a vinyl patch. If this is in an above ground pool, I wouldn't mess with it unless you think it is going to burst. Once you cut the liner more water is going to push out and make the sunken area even bigger. For above ground pools theres not a whole lot you can do. Maybe get rid of the moles....
You can't
You have no choice but to replace the liner
Vermiculite
The experts at Advanced Pool Coatings have been installing fiberglass coatings over vinyl liner pools for over 30 years. You can read more at: http://www.advancedpoolcoatings.com.
YES.
no on paint! You will need to replace the liner.
No
The answer is no. Vinyl liner pools and the concrete deck around the pool are constructed with "concrete receptor coping". The concrete deck is poured into the receptor coping which at the very bottom has was is called a "bead receptor". The vinyl liner at the top has what we call a bead, used to install the liner into the bead receptor. Because there is, and can be, only one bead receptor, a second liner cannot be installed.
There are a number of ways you could remove stains from worms on a vinyl liner. You could use cleaners.
Yes, replace the liner. Nothing can put the color back into plastic or vinyl or glass or steel.
Go to GarrettVinylPools.com and click on liners at bottom of page.
Vinyl Liner