I won't bore you with all of the details but i have had an intermittent leak since the winter of 2013-14.
I lost a foot or so of water over the winter that year. My liner floated up. In the spring i filled it back up, the liner went back into place with the exception of a small wrinkle or two and everything was fine for a solid month.
At that point it started leaking and i lost a solid 1/2 to 1 inch per day. It leaked whether the pump was on or not. I let it go and it leaked down well below the skimmer and stopped. I couldn't find any sign of a leak at that level. I filled it back up and it didn't leak for a period of time.
So basically nothing makes sense to me. It really seems to be intermittent and perhaps something with the liner?
My last question is if i had a leak in the main drain line would a high water table stop it from losing water??
Any suggestions?? I dealt with this all last summer and added so much water i never got the water temp over 76!