Setting up a 120 gal. Turtle/Orchid aquarium

[denvervet]

Hi folks, I am new to this forum. My son moved from Colorado to Maryland and my grandson Lincoln gave me his Red Eared Slider Turtles! I have recently purchased a 120 gallon fish aquarium which is 4'X2'X2'. Living in Colorado and not owning a greenhouse I cannot grow higher humidity orchids and would like to. I want to setup an aquarium which has a great environment for turtles and also will grow high humidity orchids. The tank will only be a out 8" full of water and its 2 ft. high. I plan on designing shelves for them and tend to think I may do better with miniature orchids. Half of the top of the tank will have glass on it the other half open. The light in the area is wonderful constant medium light under a flat roof huge skylight (4ftX6ft) and is great for phals. I can add shade if need be. Has anyone had any experience with this? What types of Orchids would thrive in this humid type environment. I will have some sort of air movement with fans but have not figured that out yet. All comments are appreciated!