Thanks for that Victor. That to me leads to an inescapable conclusion, (which was confirmed by more reading). That conclusion is that we only need to supply FULL SPECTRUM lighting for the biological health of the creatures we keep. This needs to be of adequate intensity. Full spectrum (5500K) has all the wavelengths, and is all the creatures need. It seems to me that all the actinic supplementation we do is for our own benefit, as we have eyes and corals do not. There might be a downside to just having high intensity full spectrum lights. That is it seems nuisance algaes do better when all wavelengths are present. That however, is just my own obsevation, and may be incorrect.
Actually when I look back to very early in this thread, I am only confirming what Steve has already said.