I had the opportunity to go behind the scenes in the Amphibian house at a Chicago area zoo (don't want to get anyone in trouble) and they had a cold water humidifier on a timer that mists on and off through the day and night for short time periods. They attached pvc tubes to where the mist would come out and then the pvc tube went up into a T then split to multiple tanks. They said it needs to be filled with reverse osmosis water everyday. I was going to rig this up but found a pet store going out of business and purchased the "repti-fogger." I set it up on a timer during last summer when I was traveling and I had a friend feeding for me. My tank ended up really really wet, but it worked. Either method works well.