Actinic lights question

[haninja]

<span style="font-family: Tahoma;">I have read in a few post opinions as to actinic light being “visual” only as in enhancing coral colors.</span>
<span style="font-family: Tahoma;">Doesn’t actinic have ANY benefit to the reef other then for our viewing pleasure? </span>
<span style="font-family: Tahoma;"> </span>
<span style="font-family: Tahoma;">I know that most people (me included) run actinic an hour before and after their main lights to simulate dusk and dawn. I also read some posts stating coralline grows better on actinic. Then there’s the spectrum – 420 and 460 where one is blue and the other pink. What benefit are they other then the fluorescent effect on certain corals?</span>

 

[flyingarmy]

Actinic is a deep water spectrum and has been shown to promote growth of not only coraline algae but some softies and deep water corals prefer that actinic spectrum to the more white(visible) light. They also are great for giving a sunrise/sunset lighting situation by having them come on before your MHs or T5s and having them turn off after wards. I have mine coming on 1 hour before and 1 hour after my MHs are on.

 

[haninja]

Thanks Mark. Anybody else?

 

[victor626nj]

im quoting assult
The sun has many spectrums, when filtered through water, the first to be lost is red, then orange, yellow, blue penetrates through water the deepest. Shallow water species can be kept under 10,000k but deeper water species should be kept under 20,000k lighting. Actinic peaks at about 420 nanometers, and while it cant be used to replace daylight lighting,it is used for supplemental lighting, and is beneficial to photosynthetic invertebrates.

Yeah, those pretty blue lights do benefit coral.

 

[cameron]

Here ya go from a post I made a long time ago:

Actinic are blue spectrum lights. Which nm depends on the manufactorer. Generally speaking actinic is more purplish since it usually falls below 450nm.

An exchange with Borneman (who I consider an expert on this matter) stated the following to someone who said it is decorative only:

Now, if you have a tank that is mostly lit by metal halides and there are a couple of normal output actinics, it may be relatively small by comaprison. But if you have a tank lit by normal output lights, its a different story. If you use VHO actinics, its a different story. Actinic lighting is a special spectrum, sure - yes, its aesthetic, but it is also functional...as functional as any light soruce for corals and the spectrum part, while duplicating deeper water spectrum, is also functional to shallow water photosnthetic life.

You can read the entire exchange at