Hey everyone, I finally have my tank where I want it for the moment, so I figured I would put up pictures. It has been running for about five months now, and the orchids are loving it!
First, a little bit about the setup:
It is a 35-40g hexagonal tank, and the cover was made by myself and my father (who is very technically gifted). The bottom of the tank is lined with 1" sections of pvc pipe to provide a drainage area, then covered by nylon mesh for soil retention (the mesh is window screen). The soil is a mixture of coconut husk and whatever orchid mixes I had on hand. The branches are pieces of cedar from my backyard - cedar wood is very rot-resistant.
Technically speaking, the real beauty of the tank is the fan mount, which lifts off to provide easy access inside the tank. The fan is connected to a flap, and it toggles between being at an angle blowing into the tank, with the flap closed (daytime), and flush with the top of the tank to provide circulation with the room, with the flap open (nighttime). Hard to describe, but a really beautiful piece of work on my father's part.