Well I was in the market to and am buying off of goreef.com and they have a write up under their ATI bulbs as follows...
"Fundamentally, we differentiate the light colors for the marine aquaria between :
1. BASIS lamps, which are used for the main lighting, and
2. COMPLEMENTARY lamps, which permit a mixing of color variations .
Our Aquablue Special is recommended as a proven BASIS lamp primarily because of its high blue apportionment , which eliminates the need for extra blue tubes. Therefore, it has become one of the most reliable T5 tubes and is the main pillar of our ATI tube concept.
The COMPLEMENTARY tubes, such as ATI "Blue plus" and ATI Actinic, should be applied in accordance with the type of the cultivated corals and animals in the aquarium, and should be more or less mixed together, but never to exceed the number of the Blue tubes installed.
So, with these complementary tubes, you have the possibility to vary the colors in your aquarium, and thereby , to react accordingly to the types of corals you have cultivated (i.e. flourescent or, placative colors) ."
So basically don't overdue it on the actinics if you want to maintain growth.
I have a 6 bulb to that Im replacing and Im doing 4 ATI 12000K aquablue specials and 2 ATI Purple Plus.
You could do 3 12000K 2 Blue Plus and 1 Purple Plus but I like the growth that can come from using the 12000K bulbs and they are still pretty blue and the Purple PLus will really make your corals POP!
Hope that helps!
Cheers!
Ian
