This is an old thread, but one that I don't beleive has been fully addressed. I was into fraggology for many years, and a lot of the above topic is frequently discussed among many reef keepers as they are constantly trying to improve both the color spectrum and the watts/gallon. The latter doesn't apply directly to our growbeds, but the concept should be noted as it sheds light so to speak on the pentrating limits of water. And on the watts per sq inch which will have profound impacts on the indoor grow bed. It's of my opinion, that the Kalvins are more important in general.
Many reefers will have for instance in their PC's will have one bank of more of the blue, or actinik lighting, and the other a 50/50 or something along those lines. Some of this is for aesthetics, while still more of it is used for the zooanthalea algae that require it to continue production in the soft mantles of clams and many anenomes. This is a far broader topic than I could possibly cover, and has a great many different opinions and changing technology on. I have noticed that the industry now is moving more towards high powered LED's to reduce the heat production from metal halides and reduce power consumption while increasing production. Google a couple reefing forums, talk to a couple hydro shops and you will see what I am talking about. There's more than one way to skin a cat.