FishDog;3304649; said:Yes it will definitely need top bracing. The acrylic won't break at that thinkness but it will bow like crazy. If you are doing one open topped like a pond set up you could do a 3-4 inch lip on the top and then water test to see if it bows. On my 72"L 27"W 24"T I did a 2 inch lip with 2 front to back braces. Mine was made out of 1/2 inch. You could also try to make an angle iron top trim piece but it better be thick cause that tank will have a lot of weight in it.

