Leak detection - 28K inground vinyl

[Poconos]

Ben is right. You need to be right at the leak point to see the dye being sucked in. Also as he said, the trick is to not have much movement. The leak test jig I made is a long piece of auto vacuum hose, skinny stuff and cheap, taped to a 10 foot length of 1/2 PVC pipe. The business end sticks out a few inches so you can position it where you want. The other end is jury rigged to the nozzle of a small garden sprayer filled with dye. You can use cheap black electrical tape to temporarily hook the hose to the nozzle, or get fancier and more permanent with silicone seal. Position the hose where you want and give just a little squirt as you move along seams or other suspect areas. For dye I use fluorescent red dye tablets that I scarfed from a chem lab where I used to work. I suspect you can get dye markers at a dive shop and make a dye juice from them. Food dye is expensive. Some people use phenol red, the pH indicator. I've never tried it but have suggested boiling raw chopped up beets and using the red liquid. Eat the beets afterwards. Finding a leak takes a lot of patience. You say the liner is only two years old so I'd look into warranty issues too.
I found a deep end leak years ago and did a lot of experimenting trying to find the best technique. Never had to get wet, even for the patch.
Al
Edit: I was told by the installer at the time that if a seam goes it will typically go in the first couple years. Mine was a lot older than that and in my case it wasn't a seam. Looked like something sharp cut some slits where the bottom transitions to the side at the deep end bowl.
(ajs-1)