I use Forest Floor and love it. I've used it for years. If you don't need it moist put it in a tub and let it sit out for a few days. But adding it to the cage and letting it dry out there should not present any issues.
Glass tanks usually do suck at holding humidity but that is because of the large screen top. Not having one you are holding more humidity.
To drop the humidity a bit you can add a oscillating fan on the other side of the room from the tank. I have to use one in my snake room too.