Powerhead position - where should I place it and which direction should it face?

[Bubble_B0y]

i'm confused....

should I position the powerhead at the bottom of the aquarium, to stir up the fish poo

or should I position the powerhead at the top of the aquarium, to cause more surface movement for gas exchange

 

[reefdiver]

I have one in my 75 on top middle. I think it stirs up the water good top and bottom.

 

[Keybler]

I go more towards the top 25% of the tank. if you put it near the bottom make sure it is aimed alittle above the gravel.

I also consider the water flow of the entire tank.