First, welcome to the forum.
As far as Equinox is concerned, it is a very capable detector out of the box in ANY mode and at that mode's default settings. So while learning the detector and what it is trying to tell you about what is underneath it's coil, I recommend sticking with Park 1 and getting used to the detector without mode hopping or tweaking settings other than doing the noise cancel procedure and ground balancing as necessary.
That being said, in fresh water Park 1 if your focus is on high conductors (silver/clad coins, copper, and silver jewelry) Park 2/Field 2 if your focus is on mid conductors like nickels, relics, or gold jewelry. If you find 50 Tones overwhelming you can back off to 5 Tones.
Since you are not just limited to the optimal targets in the Park and Field modes (i.e., Park 1 though optimized for high conductors will still hit on gold just as Park/Field 2 will hit on silver/coins, though they are optimized for mid-conductive jewelry/relics, respectively), I would keep it simple and just go with Park 1 in the water if you feel comfortable playing around with it on land.
Beach modes compromise salt beach stability for a slight hit on depth, so no need to go to beach mode if fresh water hunting.
HTH.
