... I dont know anything about an "eagle eye" loop.
But, I can say that the depth of detection is far too complicated to answer with just a simple, "It goes this deep, or that deep..." Much depends on what you want to hunt for and where.
Some here can tell you how much they get in air testing and maybe what they are getting under actual conditions - but what they get is not going to be precise for your conditions.
Suffice it to say that it is a highly engineered scientific instrument and is one of the deepest seeking detectors on the market. By some accounts, THE deepest one (at least in the All Metal mode).
I dont have a 2500 I have a 1350 - and it is as deep as I want it to be and more. I suspect that you will find little else that handily beats the 2500 in depth.
As for hunting in "ground with too much moisture." Can you define that? What I mean is, you can take a 2500 to a lake and throw it in the water - that surely would be TOO MUCH water.
- But, a little dampness? Not too much at all.
- Do you want to hunt after a rain or even in the rain? Go ahead, but cover up the controls when it is raining.
- Are you looking to hunt in muddy conditions? Go ahead if you feel like getting that dirty.
The searchcoil is waterproof, so anything short of dunking the control housing under water will do. In fact, detectors work better when soil moisture levels are elevated. Whatever you do, just be sure you protect the control housing (and maybe the battery pack) from water.