Powerhead placement / aim

[TheReefGeek]

If you have 3, I would do:

One across the back wall of the tank. One in a bottom (say left) corner pointing up and to the middle of the tank for surface agitation. Last one in the opposite (right) corner or where convenient, intersecting the flow from the one pointing to the surface for some random turbulence. I would put the one on the back and the one on the right on the timer so that you always have surface agitation.