It seems, yes, in theory. However, don't forget that strength is needed for much more than the water weight. There's the weight of objects in the tank. For example, more dense rocks, with their sharp pointy corners with their added weight resting on a concentrated point on center of the bottom glass. Add to that the occassional bumb or drop (within reason) of that rock inside the tank. Add other stuff like a stand that's 'reasonably' out of level. Add to that external long-term stresses like pump vibrations. Add more glass just for safety: such as a kid (or an employee) 'reasonably' bumping the tank with a toy. So I'm thinkin that the thickness of the glass is far far far greater than needed to support just the water -- either fresh or salt.