If you want to insulate the tank, there are a couple of things that are good. The first is called foam board. You can get it at Wal-mart in the school/ office supplies section, usually next to the poster board stuff. Another option is styroprene insulation. You can get it by the sheet at most home improvement stores. You can use either one of these to tape to the sides of the tank to insulate it. As for the screen top, You can also use these same materials or cardboard to close in the top. I cut one piece the exact size of the screen and then cut it into smaller panels about 4 inches wide. Then I wrapped each panel in aluminum foil. This helped keep heat and humidity in and also allowed me to add or take away panels as necessary to maintain the temps/humidity...

Rob