Well, I lost 3/4" of water in the pool yesterday and there was not a party
Tonight I start the bucket test to determine if it's:
a) the main drain (YUK!),
b) the 2 returns under 8' of stamped concrete, or
c) the sheer descent that's in the coping under 8' of stamped concrete
My bet is that it's the main drain due to wet block joints in the retaining wall about 5' down from the top . I'll know after checking for 24 hours with the pump running in each scenario, then 24 hours with the pump off/pressure off.
In the meantime I may have to look at getting the scuba tank hydro-stat'd and trying to squeeze into the wetsuit and doing thorough exams of the bottom then some dye testing...
Any other ideas?