He is right about the water table but it would have to be very high water table. Basically, if the leak were at the light and the water table was at the skimmer, which I seriously doubt, then the pool would leak down to the same level as the water table. Water will always seek its own level and where the pressure is equalized. The skimmer is not that deep so if you dig a hole next to the pool to the same depth as the bottom of the skimmer and you don't see water, then the leak would be at the skimmer level and not the pool light level.