400W MH's inhibiting Photosynthesis......

[Delphinus]

Interesting to see hard evidence of a potential point of diminishing returns.

The one possible caveat I can potentially forsee is this. I thought that, at least in some cases, we see more vivid coloration in corals under higher intensities as compared to under lower intensities, because the corals are using pigmentation is a means to reflect AWAY unneeded/unwanted wavelengths. Without this "extra unnecessary light" growth may be OK or even optimal, but the colour of the coral is a sort of dull tan or brown. More interesting to see the pinks and the purples and the greens and so on.

But, considering I just switched to 2x250W's from 2x175's, I'm happy to learn that I might not need to go to 2x400's down the road (unless I go with a deeper tank, of course...) :D Whew, dodged a bullet there! :D ;)