I live in Colorado, and the moisture is far from snake-ideal here. I've noticed my BP's eyes have been getting dehydrated. I need ideas on keeping moisture in my terrariums. I've decided to stick with tanks because I only have 2 BPs and I just can't afford to build a rack (yet).

Anyway, I'm using aspen bedding and my tanks are 40gal and 20gal (trying to find a bigger tank on craigslist for my male.) Anyway, putting a very thick towel over my cage has done seemingly nothing, and I sprayed the sides of my tanks and it just drys up really quickly... ideas?

I've tried turning off my lamp and the tank gets really cold. :/

By the way, is a 20gal big enough for a medum sized male?