what does actinic lighting do for saltwater

[polarbear]

well my brother has a saltwater fish only tank with live rock and sand along with some GSP and mushrooms. He was asking me what the benifit of having actinic lighting was. well i tried to explain it but i was not 100% sure myself. So im asking you guys. please respond with your thoughts

[+Jakedoza]

From my understanding it does two things.

1. aesthetics.

2. the blue will help mimic the light spectrum at certain depths. The more the blue, the deeper it will mimic. Blue wavelengths are transmitted to greater depths of the ocean, while red wavelengths are absorbed quickly. Water molecules scatter blue wavelengths by absorbing the light waves, and then rapidly reemitting the light waves in different directions. That is why there are mostly blue wavelengths that are reflected back to our eyes and the water appears blue... same reason the sky appears blue as well.. (water particles in the air)

[+mcallahan]

jake pretty much hit it. They are for looks mainly. I do see some pH rise once my actinics come on, so I know I'm getting some photosynthesis going. But they are really just there to make the colors pop.

[offroadodge]

It makes the corals that flouresce, flouresce more vibrant

[Timfish]

In addition to Jakedoza's reply a lot of corals use florescing pigments most of which absorb specific wavelengths in the blue part of the visible spectrum and re emit a different color so by accentuating the blue part of the spectrum the coral's colors are more vibrant. One of the things that intrigues me are the corals that are only found at deeper depths - this argues that red, orange, yellow and maybe even green light may actually be harmful to the coral.

[+Jakedoza]

nice to know I feel like I know something.

[Derekreefer]

Actinic lighting (420-460nm)provides the necessary light spectum required by zoozanthellae algae.