I use it in all but one of our snake's cages/tubs and it works great for the humidity. The problem is when its completly dry you have to mist it quite alot through out the day, at least I do, on average about two or three times a day for a 20 gallon. But it is the only thing that works for me so its worth it.

Takes about 20 min to fully expand (sp?) then dry it to the point of being damp, but not overly dry, and it works great.