I need some help getting the settings correct on a Hummingbird 596c HD (sonar only). When I am out fishing in about 10' of water I can see fish but they don't show up on my fishfinder. I have tried resetting to factory defaults. I have the fishfinder wire to my cranking battery not my trolling motor batteries. I also have the transducer that came with it, transom mounted & I have one for my trolling motor (US2) & they both do the same thing (display mostly clutter). Any help would be appreciated.