Nikki - I have it hanging and I believe we have the same 45. It's the 24x24x18.
I currently have the lights as follows : White - 75%, Royal Blue - 70%, Blue - 75%. They are on the hang kit about 16" over the center of the tank going longer front to back. I have the standard out of the box opics.
My real goal was to have a more even distribution of the light, so that the fall off won't be as much at the edge. Thank for the link and the insight.