Since the incubator has that rack in for turning and it stops three days before hatch, I just left it in. It kept the eggs from being tossed around by the hatching chicks and I took the chicks out once they dried some. Worked out good.
Close the vent more. I had the same problem. Instead of opening halfway per instructions, I had to keep it 1/3 open. It kept the humidity right where I wanted it.