TropTrea
New member
Interesting stuff Dennis. This most recent article is the first time I've seen anything on red light and photinhibition.
It still doesn't tell us anything about red light in aquarium lighting beyond the very general "too much is not good". To make this meaningful we would first have to know what the light levels of various red frequencies is in different types of aquarium lighting. Next we would have to construct some experiments to vary the red light on said lighting to find a point at which red light appears to affect the health of corals. Lastly we would have to repeat those experiments to validate them...
Has anyone ever put that much light of any type over an aquarium without bleaching? There are so many things affecting a corals health and this is ability to respond to stressors.
You know, looking at this last statement, it is entirely possible that, in our aquariums, corals are even more sensitive to red light.
The original long article or paper did exactly what your talking about. I believe it was over 50 pages long with about 40% of it being completely Greek to me. But the end summary of the results was very plainly stated. Basicly it stated that:
In Nature Shallow water corals receive almost 10 times the light they realy need if you eventuate on a PAR bases. Some corals detect when they are getting too much light and shut down when they are receiving too much light. The mechanism they use to indicate when they are receiving excessive light is there detection of light at 630 or more nm and especially at 680 nm. Excessive light at any wave length can be detrimental to the corals if it is not in proper balance that allows the protective properties to be triggered. Different Corals have different limitations on how much light is excessive and shuts them down while others corals may may not have reached there threshold of adequate usable light at this same quantity of light. Shallow water corals have a stronger regulatory system than deep water corals because shallow corals receive more red light as well as more light at all wave lengths.
The total jest of the article I got was you cannot put all corals in the same bucket for lighting requirements. With a fairly flat spectrum some corals may do best between 60 and 300 PAR while others would do best between 250 and 1000 PAR under the same spectrum. In ideal situations you will match the spectrum that the corals normally receive in nature before they reach the trigger point where they naturally shut down from excessive light. This spectrum might be 12,000K light for some shallow water corals but for moderate to deep water corals it could be well beyond a 20,000K spectrum to the point the K scale is useless.
As I try to tune my lighting I look for the max peak in the 440nm to 460nm range. From there I want the intensity to drop in half for roughly every 10 nm I go below 440 nm and to 60 % of peak for every 45 nm above the 460 nm range with near 0 light above 640 nm.
However even this does not work for all corals as some that may require an extremely high PAR would require so much light that I could still be burning some of low light corals if you do create a proper mix of the corals.