Tim, thanks for the advice. I'll probably wait and see if mold starts growing under the plastic before I do anything. If I end up doing something, I'm leaning toward putting a thin layer of gravel or sand on the bottom.
I'm already wishing that I had a twenty gallon tank, but my wife only has so much patience for my hobby.
I want to get a large orchidarium (something like the larger Exo-Terra tanks) for my intermediate plants, but I'm going to have to save up for it and convince my wife that it won't look too ugly. Part of doing this small tank is to get some experience before I create a large one.
Bryan