I would highly recommend the "Current USA Outer Orbit 48" fixture!

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=12779&cm_mmc=Shopping%20Po rtal-_-PriceGrabber-_-Fish-_-Outer%20Orbit%20(4&ref=3475&subref=AA&GCID=C12188x004&ctt=61