You push the ground ballance button like your going to manually do it instead of holding it down while pumping it and just above that button is a lower and higher + and - button so first do a hold and pump to get your gb number then pust button gbutton once and let it go and then using that + and - rocker button above it manually knock that number down 10 to 20 numbers lower then repush the gballance button to come out of manual mode and your done.
If you want it back do another push and hold and pump to ground grab and reset gballance to it's true reading regular.
