Thanks for the input guys! I actually will be housing a snake though.. I just really like this site for the vivarium info so my temps will need to be a bit higher. And I wasn't planning on just slapping a uth in there by itself.. I was going to try to seal it with silicone or wrap it up with something.. I just really need a way to provide more heat with out a lamp. And I do know that the underground hide will be more work, but I like the constructing part. In the process of building my waterfall now