Window glass is cut to size and taped onto the rim of the pet container. In this case, since scrap glass was being used, the cover ended up in three sections. The right and middle panes were securely taped down with electrical tape, while the left pane was only taped down along the edge that joins the middle pane. This allowed the left pane to be lifted from one side, which provided a door for the vivarium. Taping down the glass provides some measure of security, since it would not be good if the cover slipped off accidentally. 

     The edges of the fixed panes were taped only near the corners so that air will still be able to circulate into the tank from under the edges of the glass and through the seams between the panes.

     The glass cover allows more light into the vivarium, and keeps in the humidity. Having the cover open along one side means that several tanks can be set side by side, a light fixture can be placed over all of them along one half (beware of overheating) and the doors will still be accessible.  Other possible modifications would be to install a drain holes, tilt the entire array of tanks on a rack with a drainage tray underneath, and attach sprayer nozzles powered by a pump to each tank for automatic misting.