[Anselth]

Dentoid, from what I've seen, the closer the kelvin rating of your main lighting source is to 6500k, the better photosynthesis progresses. My understanding is that 6500K is the color temperature of actual sunlight, so it is more easily photosynthesized. A quick discussion of photosynthesis:

When plants photosynthesize, the particular photosynthetic compound, chlorophyll for most plants, although not always, is dialed in to a particular wavelength of light. Red macroalgae, for example, photosynthesizes red wavelengths. As your color spectrum moves from 6500K daylight standard to say 14000K, you are moving into the bluer wavelengths which are less energetic and less likely to be photosynthesized by the zooxanthellae. while there are still white and red wavelengths present, they exist in a smaller ratio. While PAR may stay the same, I'm not sure that PAR measures a specific wavelength, just the amount of useable light that makes it to a certain depth, regardless of the wavelength.