If this is plain clear plastic/acrylic sheeting, my experience if that is will sooner than later start to bow inwards. Better to go with cut glass or better yet, use Lexan or another polycarbonate sheet. It won't shatter and won't start to bow.
Thanks Ben. That's a great
I was considering using it in strips that would cover where there is any extra spray (over air bubblers), near filter outlets, etc...
I haven't figured out if I'll keep it small and attach pieces to the lights (in potentially vulnerable areas) or run the strips across the tank and try to reinforce them so they don't bow. We'll see. For now, Dan has given me an idea for resuscitating my long light. I'll see if that works first.