[Linked Image from avdil.gtri.gatech.edu]

Didn't know what a ground probe was, had to google it. And would not think it would hurt the situation. As it refferance voltage in the tanks water. As for if you would get shocked depends on a lot of factors, position of your hand between fault and ground potential ,and duration, ect. But I'd say you would be safer with one than without.

Mark Heller
"Well - I oughta....." -Jackie Gleason