What exactly IS blue actinic light?

[sen5241b]

What exactly IS blue actinic light? How is it different, if at all, from a bulb with blue colored glass? How is it different from regular T5s or MHs? What does blue actinic supposedly do for coralline? Spectrum?

 

[bjohanson1234]

I know this isnt very technical, or very specific, but I know that flourecent lights work by exciting the "phosphors" on the inside of the tube. Different phospours release different wavelengths of light. If you just took blue plastic and covered a regular old flourecent, it will act as a filter and only allow blue light to pass through. It wouldnt change the wave length or the amount of light coming out of the bulb. As far as I know, actinics are mostly used to make the corals flourece and make their colors pop. You can see this by the fact that usually actinic PAR ratings are less than a full spectrum bulb(using same brands as comparison) Next time you look at a t5 for a reef tank, look for the spectrum graph on the outside of the box. Actinics have a large peak usually around 420nm and not much else. Where as full spectrum bulbs have a small peak there and then another peak closer to the yellow/red range.

 

[Solarfall]

When sunlight hits natural reefs the water filters out more and more spectrums of light the deeper it goes. Since our tanks obviously aren't going to be as deep as the ocean, bulbs are made to emulate that spectrum to cause florescence for corals.
That's why you'll always get better SPS growth with 6,500k-10,000k bulbs and generally better softy growth with 20k+ bulbs. SPS resides at low depths where the sunlight is barely being filtered and soft corals are found much deeper.

As far as how they're manufactured... I have no idea.

 

[Rufio808]

Actinics make my tank look awesomely blue. I recently swapped the 10k bulb for another actinic. I'm glad I did and I think my fish are too. They didn't really like the intensity of the sun blazing upon them.