At first I thought this was and easy fix post but then you concerned me with the 20 - 30 % sentence ..... Sammiebob is right on the money we need more info to help, I am going to assume you are using a heat lamp according to the extreme low humidy levels your inquiring about .... Heat lamps are humidity's worst enemy unless you have time to spray or mist your enclouser three times a day. A picture or description of your set up will allow us to help a lot more