Substitute for HDPE in BB tanks

[Al]

Has anyone used acrylic sheet to protect the bottom of the tank instead of cutting board in a bare bottom tank? I'm concerned that the acrylic might warp and not look good after I stack the LR on it.

[MargieInAZ]

I painted the outside bottom of the tank with a sand-looking flexstone spraypaint.
It looks good, reflects light, and I don't have to worry about stuff getting trapped under anything or anything warping.
Eventually the bottom will likely be covered in coraline anyway.

[Al]

Thanks for the advice, Margie. I'm thinking now I'll just place the rock directly on the glass and let the coralline provide the background color. It seems that many people do without anything getting broken.