Thoughts on lighting

[Aquattro]

Just a thread from Eric Borneman I saw...

"orginally posted by EricHugo

As far as actual reef lighting, I disagree that it would take 2000 watt metal halides. At the surface of my tank, I have irradiance levels approaching sea surface values for the tropics. But, most of our corals aren't coming from sea surface values of the tropics. They come from some amount of depth, easily equalled by many types of lighting. As for the specturm of light, I don;t care and neither do the corals. In the rainy season, their water gets green. After storms, its brown. On a great day, its blue. After spawning, its cream. When a cloud passes overhead, its dark and red-shifted. When its sunny, its turquoise clear. At dusk and dawn, its red-shifted. If a coral gets shaded by another coral or algae or sponge, it gets less light than it did. If a storm breaks it and it falls down under a rock, its gets less light. If it fall from an area of lower light into an open area, it gets more light. Corals grow in deep water, shallow water, etc. So, to simulate natural light levels might take a lot of light, might take a 24" fluorescent. Could be any spectrum, depending on what the ocean is like that day.

The whole lighting issue has been almost laughable to me for years.

Depending on the coral, they can adapt to fairly huge variation because they have such good photoacclimatory responses. Most corals saturate at or well below 20,000 lux or so...about the equivalent of a single 175 watt metal halide halfway down an average size tank. So, photosynthetic requirements met, end of story for all practical purposes...from there, it becomes a matter of specifics to a coral or aquarist and what they want...or think they want.

I care that corals live for aquarists. I care little if they are the color they want them to be, if they have a 10000K bulb or a 12000K bulb, or if they think their lighting can ever be "ideal" - if there is a question about where a coral is found, and if it needs a lot of light or has specific light requirments, I deal with that. I hate lighting banter, in general, cause I think its techno-babble that is for the most part absolutely irrelevent beyond a certain stage. Zooxanthellate corals need light and light is important for them. We have a thousand ways to provide them that light. Have had it available for going on twenty years. What else is there? "