LED Switch moving away from Orphek

I learned a lot through various biology and biochemistry courses and by working in a molecular biology lab as a research associate, using coral pigmentation genes to trace retinal development in zebrafish.

Also, reading a lot of scientific literature and hobby literature.


Anything by Dana Riddle is usually pretty informative:
Advanced Aquarist's Online Magazine
Ones on pigmentation are good, such as:

Feature Article: How to Make Corals Colorful, Part One: New Information, With Particular Attention to Blue-Green Fluorescent Pigments — Advanced Aquarist's Online Magazine

Feature Article: How to Make Corals More Colorful, Part Two: New Information! Green Fluorescent Pigments, Pigment Clades, and Photoconversion from Green to Orange/Red — Advanced Aquarist's Online Magazine

Feature Article: How to Make Corals More Colorful Part 3 - New Information: Red Fluorescent Pigments: DsRed-type — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration: Fluorescence: Part 1 — Advanced Aquarist's Online Magazine

Feature Article: Effects Of Narrow Bandwidth Light Sources On Coral Host And Zooxanthellae Pigments — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 2: Fluorescence: Pigments 510 - 565 and Notes on Green Fluorescent Proteins — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 3: Pigments Responsible for — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 4: Red Fluorescent Pigments, a Preliminary Report of Effects of Various Environmental Factors and Color Mixing — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 5: Non-fluorescent Chromoproteins (CP-480 to CP-562) — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 6: Non-fluorescent Chromoproteins (CP-568

Feature Article: Coral Coloration, Part 5: Non-fluorescent Chromoproteins (CP-480 to CP-562) — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 6: Non-fluorescent Chromoproteins (CP-568

Feature Article: Coral Coloration - Part 7: Coral Reflectance, Chromoproteins and Environmental Factors Affecting Non-fluorescent Pigmentation — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 8: Blue and Green Coral Fluorescence: Environmental Factors Affecting Fluorescent Pigmentation — Advanced Aquarist's Online Magazine

Feature Article: Coral Coloration, Part 9: Tridacna and Other Photosynthetic Clam Coloration, With Observations on Possible Functions — Advanced Aquarist's Online Magazine


Same for Sanjay:
Advanced Aquarist's Online Magazine

Also, see:
Feature Article: Colors by the Thousands - Light, Colors and Corals, Part I — Advanced Aquarist's Online Magazine

And take a loot at "Facts Of Light" series in Reefkeeping (Reefkeeping appears to be down, so, I can't post).

 

I can't run MHs without burning corals, without slow acclimation...
I have found with slow acclimation can really ramp up the power with 3W CREE LEDs. I did have these problems at first with 3W CREE LEDs, however, IME, the corals seem to burn do to lack of correct pigmentation. It takes a while to initiate a change to the spectral properties of the LEDs (or any other change in lighting for that matter), however, once this is accomplished there does not seem to be a difference between different lighting sources. I'm really blasting some corals and they are now perfectly happy. Pigments protect the coral, without pigments they are stressed. It takes time to shift pigmentation to different spectrums...

 

The corals never had a problem under 2x250w MH with PFO reflectors and 2x140w VHO actinics but the switch to LED really ticked them off. The RBTA's, zoanthids, ricordeas and crown leather are happy but the LPS and SPS are not. I have been experimenting with intensities and time durations and just have not found the sweet spot yet.

 

No doubt, however if you had switched from XM10000Ks to Phoenix 14000Ks, they would also be ticked off. If you look at the spectral plots from Sanjays dats for example, they are completely different. If you say you can't compare LEDs to metal halides due to the spectral differences, then by the same logic you can't compare Metal Halides to Metal halides as the spectral output can vary just as much.

Now as to why the corals are ticked off, likely the spectrum is a more significant reason than the intensity. Corals can adjust to intensity by up-regulating or down-regulating genes which are already active. To switch which pigments are produced requires complex changes in gene expression profiles. This can involve various feedback and housekeeping gene networks and even more complex changes such as chromatin folding and organization. This suggests adaptation to spectral variation should take much longer than adaptation to intensity. IME this seems to be the case.

Edit: btw I'm assuming corals have the genes to adapt to certain spectral characteristics. I think corals are resilient and suspect most probably can, but it's certainly possible that some can not, at least not, or at least not well at the same intensity.

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This has some of the most informative forum posts I have ever read! but from everything I have read it seems that this subject is still subject to much more testing before people can come up with a definitive answer on the right LED fixture for reef tanks and even if the current LED's are a better option to MH's

I am looking at this fixture that blew me awat at a trade show. Obviously this is totally untested and I think I am going to put myself up as guinie pig! The specs look good though and it was the brightest LED ive ever seen!

CoralVue's 3rd Gen Pharos LED Seen at MACNA | AquaNerd

bloody hope it does a good job!