I keep a king in my PVC who does not need as high humidity as a bp but I hope this helps you. I use aspen for bedding. I had to drill some holes on the sides to add more ventilation. I also removed the water bowl now and then and it helps. Each day, when I check on my king, I also leave the door open (supervised with me standing right there) and turn on the fan to air it out for a few minutes. I know it is probably not a big deal to my kingand they are practically bomb proof but I have a pet peeve against cages that lacks proper ventilation. Even my tubs are not like this. Using the above methods, I was able to lower the humidity down from 80% to 50-60%.