Light Transmission - Oceanic Type III Water

[oreo54]

The zooxanthellae can use the 500 -550nm spectrum. But under the same intensities of light, corals calcify faster and have greater fluorescence under 450-460nm blue alone than green, red or full spectrum.

http://rrrc.org.au/wp-content/uploads/2014/03/Technical-Report-22.pdf

 

[SDchris]

Is that Tim Wijgerde's work? Someone else's, perhaps yours?

A few studies seem to point in that direction.
Light Enhanced Calcification in Hermatypic Corals: New Insights from Light Spectral Responses.

From personal exp building LED fixtures for SPS tanks years back. 400 - 440nm (violet) spread produced much better results, in terms of growth and colour rather then 440 - 460nm (royal blue).
Having started like most back then with a 50:50 white:royal blue mix. Ending up with a 4:1:1 violet : royal blue : white ratio with other colours mixed in for colour blending.
Taking the radiant output value of those LEDs into count, you end up with a spectral curve similar to a lot of 10k metal halide bulbs. Which has a nice uniform peak between 400 -500nm. And similar to a lot of T5 bulb combinations. Unlike 20K metal halides which tend to drop the violet and peak more 455nm, which is probably more similar to most current LED fixtures

 

[Ashley Kekua]

is possible to grow healthy corals with 420 nm only?? 440 nm only?