Yeah, to have 0% is not at all normal. Especially in the midwest you have to have SOME humidity, as I said, even here in the desert I am at about 30%, plus your water bowl will give off some humidity, so something isn't right. Try the wet towel approach, that will ensure the substrate stays dry, and I would get a new gauge. Misting several times a day is way too much.
Are you having bad sheds? Is that the reason for the misting? Like Mari said, at shedding time make a moist hide or two with sphagnum moss to help with the sheds. Otherwise I wouldn't worry about the humidity, only if the sheds are bad.
Another idea, if it really is that dry and you are still worried, get an inexpensive humidifier from Walmart. That will help raise the humidity in the whole room including the viv, and you won't have to mist.