Finding leak in IG gunite pool?

I have an IG gunite pool that was remodeled last year. Since completion of the remodel, it appears the pool is leaking since the level drops at approximately twice the rate it did previously. I live in the Los Angeles area. The remodel included relocating the skimmer, relocating the return lines, and adding a dedicated vacuum line. This was in addition to resurfacing with pebble tec and replacing the old tile with 1/2 inch quartzite stone. The new plumbing was pressure tested prior to being placed in service. The pool company has performed a leak detection but found nothing. i performed a bucket test and the pool level went down faster. I have now let the level drop (pump off) and it appears to have settled just below the skimmer and tile line. Skimmer still holds water. Any idea what might be causing the leak? The quartzite was not sealed. Is it likely that its leaking? Is it likely that the old skimmer (filled in), new skimmer or new plumbing penetrations are culprits? Please help.