A Dumb Q About Actinics

A friend of mine just tried to run her actinics 24 hours a day.

I can say from their experience that it is too much for their corals. I guess it would be something like having the sun out all the time for plants. If they get no rest then it is hard to grow properly.

Their clams started behaving different first, then everything.

So 16 hours may be good, but 24 may hurt the tank.

 

Their is a point when corals and their host zooxanthellae can receive too much light!!! Often this can lead to too much production of dissolved oxygen produced by the zooxanthellae with nowhere to get rid of it...leading to bleaching and declined health!

 

I have a hard time believing that. The K of Actinics has the ability to reach deeper into the water. Because red and yellow light is absorbed faster by water. But I do not believe the Actinics have any benefit tide directly to Zooxanthellae. If it was the case would we not be concerned about the PAR rating of our Actinics?

J

 

Zooxanthellae is a yellow-brown color!! Because of this the color of zooxanthellae absorbs blue actinic light better!
Take a look at it this way! Like you say water is a terrible absorber of light, it refracts light at short depths. After a depth of around 60 feet, all that is left of the spectrum is blue/purple and ultra-violet light!!! The kelvin associated with actinics is around 420-460 and is the only color available at depths, so you basically helped me to answer your question!
Corals, that are hermatypic as well as symbiotic, can grow at depths below this point where only blue and purple light is evident, leading to the assumption that their zooxanthellae are good absorbers of actinic/blue light, especially since all other light kelvin has been depeleted, so see how blue/actinic light is so important to zooxanthellae! Without actinic/blue lighting in a reef tank, many of the corals that are in there will suffer the consequences!
I hope I was able to explain it to you without confusing you!

 

I thought that since actinics exhibit such a narrow wavelength of about 460, there was no Kelvin rating associated with such lighting. If there were, it would be a relatively high Kelvin, such as 20,000.

Unless I'm misinformed, the 460 number associated with actinic lighting is not a Kelvin number.

Sunlight at the surface is 5000. A few feet down it's 6500. The deeper you go, the higher the Kelvin rating (lower PAR).

CR, I'm not disputing that corals need actinic lighting, as I've not really done any reading in that realm yet. Just hate for misinformation to be spread. ;D;D

Someone knock me into place if I'm mistaken, please.