Thanks for the replies.
Actually I am wanting to make a tank as large as possible from plywood and still be aesthetically pleasing. Plywood comes in sheets 96" by 48" so I figured the longest tank I would be able to make would be 96".
GARF Does not recommend building a plywood tank longer than 48" when the height is more than 24", so I am looking at a tank that maybe 96" long by 24" high. But how deep do I go?
I was hoping that there was some analytical way to select the dimensions for a tank this size, since I wont be able to see the end result till the end.