low humidity

[trailblazer295]

Hey everyone

I have a 2x2x1 pvc cage. I bought my first BP a week ago and all week I'm not able to maintain proper humidity. I've sprayed in the inside of the tank on both floor and side wall and 7hrs later it drops from 50% to 35-40%. I've sprayed it morning before work and at night before bed and everytime I check it again it's dropped. It being winter the air is dry, the humidity in the house is around 40%. I'm looking for a new substrate for my BP to help maintain proper humidity in winter. I'll try aspen come summer as it might be useful. With ecobark and similiar how often should it be changed to avoid mold? I'm intrigued by the use of towels as a substrate. How well do they work? What's the impact on humidity?