I had the same problem with my BP until about a year ago, when I saw this really easy and inexpensive way to keep the humidity up...use a cool mist humidifier that has a top opening with a directional outlet. I found the humidifier at Menards, but you can probably get something similar at Home Depot or some other home improvement store. You need the humidifier, some vinyl tubing, and PVC fittings to make it work...I got everything at Menards and was able to get the correct size tubing and PVC fittings there as well. Since the humidifier has a variable output control I am able to adjust the mist when she is about to shed. The humidity is running at 50-55%, and I've had no issues keeping it where it needs to be. I think the whole project cost me less than $35, which is much cheaper that buying the 'reptile humidifiers, and this solution put an end to a major frustration. I cannot take credit for this idea...I found it somewhere online, and put it together that same day...quick and easy. If you don't have a Menards in your area I think you can get these humidifiers on their website.
Pics of the setup are in my image gallery at http://ball-pythons.net/gallery/brow...mageuser=56592
If you have any questions please holler, and I hope this helps you out.
Regards...Dave