There are so many configuration options for that set up.
Most important question is what kind of display do you want to keep?
If you want chaotic turbulence I would do something similar to what rayn suggested.
However if you want more of an orderly tidal turbulence than stunreef has a pretty good suggestion.
Speaking for myself, I don't like having my circulation pumps obscuring my view.
I would keep the back ones basically where you have them and move the side ones down and back close to the overflows.
I would aim those pumps to generate either a clockwise or counterclockwise flow around the display.
Using a controller so the pumps are alternating up and down in intensity will generate irregular flow patterns and variable turbulence.
That said this is your display and I would play around with different configurations until you come across the one that works best for you.