Sorry, I didn't realize this was for a SW
tank. I should have been clear that you would need both the electronic ballasts. Each one normally drives 2x 40W NOs, but you can hook each ballast up to a single 40W tube and get ~60W out of each tube with barely noticeable drop in life span. I'm using GE plant and aquarium tubes in a DIY
gutter strip light, but overdriving the tubes will be my next project.