That depends on what your tank looks like. I have circulation pumps aimed up toward the water and others aimed down toward the sand to constantly push waste into the FX5 intake.
Two is plenty for a 135 tank. I have my Koralia point from right to left. The fish seem to love the current and water seem clearer because there is not dead spot. It really depends on your preference where you want to point. Try different spots and see what work best. I posted a thread similar to this one awhile back.