David, the tank is in the room on a 45 degree angle. So if you are standing in the room facing the windows, you are standing directly in front of the corner of the tank, not one of the sides. The plumbing is in the very back corner closest to the windows. So I hung the fixture so that when you are standing there it is horizontal, just like your light is when you are standing directly in front of your tank. And the main reason I decided to hang it this way is that it places the light in front and horizontal to the overflow box. If I would have hung the light at the same 45 degree angle of the tank, one corner of the light would have been over the overflow which is a waste and not really desirable. The only downside is the fact that the front corner of the tank is going to have the least amount of PAR. But if I want any coral there it will just be something requiring less light.