Mark,
Fill the pool to the typical water level that it is leaking and then turn off pump for 24-48 hrs [first make sure you bring your FC to OCLT test levels]. Track your water loss levels and make a note of the times. [if real windy and hot, in full sun, the rate of loss will be accelerated] .
If the leaking stops at your skimmer, then it is more likely your skimmer; if the rate of loss is the same below your skimmer, then the leak is below the skimmer, but could be the skimmer too if the loss rate decreases after the skimmer.
I know this is very, very frustrating, but there is an answer. Hang in there and let's keep plugging away...
I am still letting it fall. It is losing less water each 12 hours I mark the water level, the closer it gets to the bottom of the skimmer. You're right, it is VERY frustrating!!!!