What kind of tub are you using? Mine is a Sterilite style 34 quart. I made small holes along the side with a soldering iron for ventilation. If I want to cover some up, I can just put tape over them from the outside and the humidity level will go down. If I need less humidity, I can make more holes. That's the general idea.

I use Natural Chemistry Healthy Habitat Pet Habitat Cleaner and Deodorizer for cleaning. Costs about $20 for a gallon and I just spray and wipe everything down with it.