I have a glass enclosure with a screen top. If I wrap the screen top with plastic wrap except for 2" on each side and then cover the top with a towel it holds humidity in extremely well. I am just concerned that a total area of 4" by 12" covered with a towel may not be allowing enough oxygen in the tank. Is anyone else doing this or know if it will be ok? Right now I am just covering the top with a damp towel until I hear other wise. Thanks!