Plexiglass tank, bowed in back.
Is it normal for the plexiglass tanks to bow? It's been like this for awhile now, but I'd assumed it was from the heat (heater and lights) and the rocks piled against the back. Only a few of the larger rocks are actually touching and the bow isn't bad, so I haven't worried about it... but should I? The front and ends are fine.
Incidently, the top has warped down a little bit in the middle, but I have a 1/4" glass top on it that I had specially made. Tap plastics advised me that any plexiglass top, no matter how thick, will bow from the heat, so they suggested glass.