Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
A bridge or some other system that keeps the tanks structurally sound is best. Trying to join glass in a flat plane is not a good way to make a strong wall that you need for an aquarium. As a bottom you could get away with it because not only do you set the 2 pieces next to each other, but you also get more glass to sandwich the joint for strength. That would look really ugly, though, for sides, and even worse for the front.
Maybe work on the water fall idea.