I've been using the Soveriegn GT for a little over a year now and was confused myself about ground balancing the unit at first. This is what works for me. Before I start searching, I usually set the machine to All metal, Track and pump the coil a few times till it levels out then I switch to discriminate as this is the mode I hunt in most of the time. When operating in Disc mode, the Sovereign GT uses digital filtering to compensate for ground effects and the Track / Fix / Pinpoint function switch is disabled. I leave the switch set to pinpoint since it's disabled, then when I do need to pinpoint I can simply move the Disc. switch to all metal.