You could drop a few bits of small flake food in the tank in front of a PH and see how it moves around. You could also turn the ventrui on in your PH and see how the air bubbles move around. There are so many variables that would affect how water would flow in a tank its crazy to think about.
Moving one section of
LR around in the tank could/would change how the water flowed around the tank. Such a simple change could put an area of low flow now in an area of high flow.