FWIW, my 40 breeder GLASS tank bows front and back nearly 1/4". Its normal due to no center brace and widely discussed on the forums. I could see a larger tank, made from acrylic, bowing even more. I wouldnt stress it.
Heres an older bowed acrylic tank thread.
http://www.reefcentral.com/forums/showthread.php?t=2000526
Heres an older bowed acrylic tank thread.
http://www.reefcentral.com/forums/showthread.php?t=2000526

