I used a 6 bulb T5 fixture for a time, and tried different bulb combo's including one with a actinic. Ultimately I didn't like the overall color, I felt blue+ bulbs offer just as much pop and just work better in combination with other bulbs. Put a True Actinic next to a coral+ and the coral+ overwhelms it.
I think when using ATI's T5's its not so much a matter of giving your corals the spectrum they need for great growth(all there marine bulbs work), its finding a spectrum of colors you like to view.
On a 6 bulb I liked 4-Blue+, 1 Coral+, 1 Purple+ (I like 1-purple+ and 1-Blue+ combined for dawn and dusk. ) and all bulbs for daytime photo period.
Purple+ is a awesome bulb for fish, good pop and deeper colors, the clowns and yellow tang i had under it looked stunning blue bulbs wash these colors out.
