AT Pro, ground balance

[alwayssearching]

Been hunting with the AT Pro for about six months now. I am starting to gain confidence as I find the old silver coins and even a couple of nice silver rings.
But I still question myself when it comes to the ground balance feature. My fear, is that if the ground balance is off, so goes the hunt. I check the GB through out the day and it seems to be different all the time. 77 seems to be a standard setting, but I ground balanced, and got an 86, then, do it again, different number, and again different number.
This is the one aspect that I would like to understand.
Thanks in advance for your help..

 

[mr helton]

In Michigan, my ground balance setting seems to be 89-92 no matter where I go, so I almost never bother to ground balance anymore.