That's super important. I hung the fixture and had my wife sit on the couch as I held up a piece of cardboard to find out low it needed to be from the bulbs.Hey I love the canopy!!! I Just ordered a pair of LED lights for my tank and because of where I intend to place the tank, I am concerned about the glare of the lights from where I sit. What you made looks ideal for what I need for my own setup!!