I added 4x 6500K LED strip lights since I've read zooxanthellae respond well to that spectrum. The tank brightened up a lot and the algae in the tank really started bubbling. 6500K boosts the vibrancy of the green coloured stuff in the tank. Not everyone's cup of tea for viewing, but I only run the 6500K's during the day and the reef lights slowly fade to actinic during the course of the evening. I think the changing spectrum throughout the day is pretty cool and it highlights different things in the tank.
