I've been using Aspen since I got my BP's. Usually my humidity was around 39-43% all the time. Last week I bought some of the Coconut Fiber bedding, read the directions, soaked it in water, let it dry out for a week in a tub. This morning the humidity was a good 40% even. I decided before I leave for the day i'd go ahead and clean his tank and switch it out. 30 mins later... after i put everything back in....holy crap! 54% humidity. Talk about a difference in holding moisture from substrate to substrate. I'm all about the the 10% jump in humidity, but is moist too moist? Hopefully i won't have to worry about any cases of bellyrot in the future!