Pigment, zooxanthellae, and color.

As I have been gone for a few years, just set up another tank, and have recently been thinking of my good friend Tom, I'd like to bring up a topic he and I discussed long ago, but never received a satisfactory answer to. Anyone who is a diver knows that colors/wavelengths are filtered out of the water column, with depth, rather quickly. Reds are lost around 3-4 meters, followed by oranges at 6-7 meters, yellows around 10, etc. Corals appear colorful to us in our microcosms because of lack of depth, our choices of illumination, and the pigmentation in the zooxanthellae reflects back to us those wavelengths that do not get absorbed/used. In essence, the wavelengths we see as 'color' are what the zooxanthellae have deemed 'unworthy' or not useful for photosynthetic purposes so the pigments reflect those and essentially filter them out of the animal. The photosynthetic rxn requires photon absorption, not reflection. We have all likely seen corals change and/or lose color based on lighting/depth in the aquarium environment. This would indicate that coral have the ability to preferentially expel those zooxanthellae/pigments that are negatively affecting the energy balance (photosynthesis rates) in favor of more suitable pigments...or in hopes of acquiring more suitable pigments. Take for example the bleaching that is occurring in the Great Barrier Reef. Presumably due to elevated water temperatures (stress response) those corals expel their food source. As a fixed location organism, since they cannot move to greater depths to decrease the reaction rates (by limiting that reaction with fewer photons), and temperature is positively correlated with rxn rates, so the coral has no choice but to expel their hosts or suffer a surplus of Calvin cycle products. (evidently they can't metabolize them quickly enough...or at least that is my supposition...which leads to a surplus of metabolites which must be toxic...again, my supposition) This being assumed, our coral's color shows us that which it does not want/need in terms of lighting. We strive to get the brightest and most colorful corals, yet our lighting choices artificially accentuate those wavelengths which are not being used for metabolism. An indicator of health is pigment density, yet that pigment blocks the wavelengths of the color we see. As such, does coral color indicate the depth (light intensity) that we should strive to replicate in our aquariums? Ie. A red coral is reflecting, not using, red wavelengths, and since red is naturally filtered from the water column in 3-4 meters, does this mean we should try to keep reds further from high intensity lights? ...and if we do, once they adjust to the lower intensity, will they 'fade' to a different color by expelling some of those red pigmented zooxanthellae? ...or does this mean that the coral came from a shallow/higher intensity light area which is why there is a surplus of red pigment to begin with, so we should keep them shallow/bombarded with full spectrum photons? If this is the case, using the color spectrum (ROYGBIV) could be a good indicator of depth that the coral came from and how we should try to reproduce lighting. Thoughts?