We are new pool owners (Came with the new house). We had approx 1 inch water loss per day, and had 3 pool companies who claim to do "leak service" out. 2 could not do a thing and 1 (the one most highly recommended) said we had a "pressure side leak" but could not tell us where or how to fix, etc.
I called American Leak Detection, and it turned out our leak was around inlets and they were able to fix our problem. They did a very thorough inspection, gassed all the lines and dove into the pool to inspect the gunite and all the usual spots, it skimmers, lights, drains, inlets, etc. I was convined that we had a leak in our spa line also, and it turned out not to be the case. It was expensive, I think $180 p/hour. And they were at our pool for 3 hours. He probably could have been done in 2 hours, but had some problems gassing the jets in our spa. I was very impressed and they solved our problem. It was also evident to me that American Leak Detection has more experience with pools than the pool service companies I hired first.
I mentioned before that I was convinced it was in the pressure lines to the spa, as it turns out the leak detection rep was very familiar with the way our pool builder runs plumbing, I called the builder after and he as right which eliminated the issue as I thought.
Good luck, I hope its a easy fix.... keep us informed to how it turns out