ADA doesn't have a 12gal long, unfortunately.
Matsnork: You should definitely try getting the tank replaced. The tank appears to be poorly crafted and the silicone work is atrocious for an ADA-branded tank.
I recently had to have an ADA 45-F replaced three times because of poor silicone jobs and scratched glass. Was a real hassle but you should not be settling for anything less than perfect when paying a premium price.