I have used all 8 bulbs all along but now I have 4 new bulbs in the center 4 which I only run for 3.5 hours per day and the other 4 bulbs for 10 hours. I actually like the look of the tank with just 4 bulbs so I don't run all 8 that much. Plus, I'll be adding a Blue LED strip this week so all of this will change again...
Currently the bulbs are:
Blue Plus
Purple Plus
Coral Plus - new
Coral Plus - new
Aqua Blue Special - new
Coral Plus - new
Actinic
Aqua Blue Plus
The old bulbs are going to be replaced with a new Purple Plus, Actinic, and 2 Blue Plus... I'm pretty sure... Still learning and which bulb is which but I do like the 12-14K look I've been getting.