Lighting Spectrum questions

[BGJ223]

Well I was doing a little reading this weekend about corals, and I noticed that alot of the corals that we keep are found in the wild at the 30 meter range. So if they are at 30 meters, then pretty much the only light that is going to penetrate that deep would probably have a wave length of 420 - 460, just a guess. If this is the case, then why do we blast our tanks with 6500k, 10k, 12k, 14k, or 20k lights. Why not use an assortment of lights in the blue wave lengths?

[Doug1]

Originally Posted by BGJ223

Well I was doing a little reading this weekend about corals, and I noticed that alot of the corals that we keep are found in the wild at the 30 meter range. So if they are at 30 meters, then pretty much the only light that is going to penetrate that deep would probably have a wave length of 420 - 460, just a guess. If this is the case, then why do we blast our tanks with 6500k, 10k, 12k, 14k, or 20k lights. Why not use an assortment of lights in the blue wave lengths?

30 Meters???????????? There may be a few corals from that deep show up in the trade but I bet they are mostly non-photosynthic like Dendro/schleronepthea, Tubestra and the like. Not much light at 90 feet and collecting would be difficult
Most corals are found at much shallower depths up to the top of the reef with exposure at times and all the niches on the reef and surrounding areas as well

[BGJ223]

Originally Posted by Doug1

30 Meters???????????? There may be a few corals from that deep show up in the trade but I bet they are mostly non-photosynthic like Dendro/schleronepthea, Tubestra and the like. Not much light at 90 feet and collecting would be difficult
Most corals are found at much shallower depths up to the top of the reef with exposure at times and all the niches on the reef and surrounding areas as well

I know you are a diver Doug, so I won't debate with you that much about the depth of the corals. But the book clearly states and with pictures montipora and other SPS corals are found at 30 meters.
Seeing that the light has to travel through the water in order to get to the coral, and most of the light provided by the sun does not penetrate the water that much. Why not just use blue?
Can you not promote photosynthesis with blue wave length light?

[AquaticCo]

Most corals are not at that depth, like Doug said. There may be a few but not many. Since your reading up on lighting check out PAR and what it is and how zoanthelle (sp?) feed. This will give a greater idea of the spectrum of light needed.

Check articles by Dana Riddle, Julian Sprung and Sanjay Yoshi. Julian Sprung and Charles Delbeck's book "The Reef Aquarium" gives a very good review of light.

Doug

[BGJ223]

I will look into those. Thanks for the input.
But I am still curious. Would 420-460 wave length stimulate photosynthesis?

[Geoff]

no, it will not stimulate photosynthesis. if it did than grow lights would be blue instead of yellow.

G~

[BGJ223]

Thanks for the info folks.

[Geoff]

FYI- as you go deeper the corals will need to rely more on the other symbiots in their tissue than the Zooax. since at these lower depths the spectrum is not so hot for them to be doing photosynthesis.

G~

[BGJ223]

Originally Posted by Geoff

FYI- as you go deeper the corals will need to rely more on the other symbiots in their tissue than the Zooax. since at these lower depths the spectrum is not so hot for them to be doing photosynthesis.

G~

well then that explains how you can have SPS corals so deep.