Really? Would it still if I'm running LEDs? The unit does not get quite as hot as the T5HOs. Thanks for letting me know, though. Maybe glass is the answer afterall. Unless someone has a different/better suggestion..
I think it is a combination of the humidity and the light that causes the plastic to warp. I made a plexiglass lid for my frog tank and the corners lifted up in less than a week. I used 1/8 inch plexi, I don't know if the lid will fare better with say a 1/2 inch or 1 inch lid.