Welcome Mike. Like I just said in another post, good luck getting someone out to look at a leak, especially this time of year.

Does it leak down to a certain spot and stop? Stop adding water and watch this. It's an easy first step to determining your leak. A tangent to that, does it only leak when the equipment is running?

How much water are you losing?

You're doing good to look for external signs (dead grass, though pool water isn't the cause). Any sunken areas?