Let's start with the bucket test to see if you have a leak. If you go to the subforum called "Inground Pool Construction and Repair," you'll find a stickied thread (4th thread from the top) about how to do the bucket test. Report back with what you find out. I'm also going to ask PoolDoc to look at your thread as I don't know much about these plaster/gunite pool finishes.

Welcome to the Pool Forum!