nothing for nothing, but 3-3.5w of full spectrum/10k or higher + a couple of blues.....should make your tank purrrr.......
throw the 6500 out, and get 4 good Geismann bulbs. ( thus roughly 250w whats of true) and keep your two actinics for aesthetic purposes.(thus roughly 130 of color enhancement)
should keep things rockin' along just fine.