[dgasmd]

Actinics do provide some measure of light that is usefull to corals. I think one of the points Dana Riddle may have been trying to make is that actinics do more for us than for the corals in the grand scheme of things. Regardless of the MH used for growth (well, almost) the corals will grow the color it has. You switch lighting and they look either better of worse to your eyes. The pigments that flouresce and cause colors perceived by our eyes have been there all along. The difference is that now the different MH kelvin rating may make them flouresce more or less. That is why actinics always make corals look so much better. It is not that they have some magic that make the corals produce more colors, they just bring them out because it allows then to flouresce more. I know this because he gave a talk to our local club about 1 year ago and he went over this and it caused a lot of questions and such. By the way, as you can see, he made it out of the meeting alive though.
Of course, even if you don't use actinics, you will see a change. In some corals faster than others. It does take time for the coral to adjust its priduction of pigments and other things based on what lighting it has. Once it gets adjusted to it again, the colors seem to settle and continue.