Length or Height more important for tank?

[michika]

What do you think you want to keep for livestock? If you want say tangs, I would recommend length, but if you are going for seahorses per say, I would say height.

As for depth, I have an 18" deep tank now, and occasionally do find it challenging to find rock that will fit, yet won't be too close to the glass, or in my case, clams.

If you could do it, I would say go deeper!