Ok so you are correct Whites are messy. Mine are filthy little pigs sometimes. I put a waterfall in my terrarium, I used the Amazon.com: Tetra Decorative Reptile Filter for Aquariums up to 55 Gallons: Pet Supplies . I went with this so it would filter the water since my girls are so dirty. I change the filters every 2-3 weeks and the water about every 4-6 weeks. Depends on their level of dirtyness that month.

I am not sure about all Whites but my whites DO NOT like to be in the line of spray at all. They tend to spaz out and show me their back side while they pout about what just happened.

I have the waterfall and I have covered 1/4 of the top with glass and I use a ReptiFogger set on a timer for 3 minutes every hour. This manages to keep my humidity at about 65-70% on a regular basis.

Hope that helps. Let me know if you have any other questions.