Axiom not marking fish

[JimBognr]

Update on the issue with loosing bottom at random. I just completed a seven hour excursion with no bottom loss at all. I fish with a Tracker Pro175 TXW welded aluminum boat. When I installed the Axiom, I connected the ground terminal on the back of the Axiom to the hull. I disconnected the ground before my last excursion, and it seems to have solved the problem. The ultimate test will be a trip back to the strip mining pits, where the issue was most prevalent. Do I need to connect the ground terminal on the Axiom to the negative side of the power source, or can I just leave it open? I assume it is also grounded to the power supply through the power connector.