Anyone use sunlight instead of metal halides?

[evilnewbie]

I am curious if anyone has used natural sunlight instead of metal halides for their corals... was it a good/bad experience and what city did you live in... thanks.

[reefhead728]

never tried. Im also from sc i would say trying to use sunlight would be hard if impossible to use becouse there are going to be some days when your tank will not get enough lighting if any at all.

[Parrothead]

I think even if we could do it, I believe heat would be a major issue unless you ran a chiller, and placing the tank I think would be an additonal issue, definetly do not want it outside. JMHO

Tanks,
Robert

[Doodaa]

Evil,

How are you thinking of getting the sunlight to your tank? I've seen a place that pipes it in with fiber optic cables and I think they had great success.

If you just stick it in a window, I don't think you'll get enough direct sunlight on each piece of coral as they would get normally in nature. Plus depending on the window glass, there may be some tinting or filtering built into it. It would be a good supplement though.

I have my refugium/sump that gets some direct sunlight through a south-facing window...I have not seen any ill effects of that at all except I get algae growing in my CA reactor until I covered it with a towel. The stuff in my sump/refugium is growing quite well...haven't had it in there without the window, so I have no comparison.

[Ninong]

Yes, lots of people have used sunlight over their tanks. It works out better if you are closer to the equator. For example, it's a lot easier to do if you live in San Diego, Brownsville, or Key West than if you live in Seattle.

The Waikiki Aquarium in Honolulu has an outdoor reef tank and an outdoor lagoon reef exhibit (7,500 gallons). Both of those are completely open to the sky and use only natural sunlight. All of the Waikiki Aquarium exhibits receive natural sunlight, even the indoor exhibits, but those use supplemental metal halide lighting.

The new 212,000-gal reef aquarium at the California Academy of Sciences in Golden Gate Park in San Francisco receives natural sunlight but it also uses very powerful metal halides. This aquarium doesn't look good at all. It's obvious that it's not receiving enough light for corals. I'm surprised that they didn't properly calculate this lighting situation in advance. This is a very deep (tall) tank. I believe it's something like 19-feet deep. I was very disappointed with this tank when I saw it last month.

Some people have managed to use just sunlight plus fluorescents of some sort. Other people have used sunlight in addition to metal halides and fluorescents. There have been several very lengthy threads on this topic on that other really big board.

I will give you a couple of examples as food for thought. This beautiful reef aquarium is set up in a greenhouse-type addition to the home. That new family room that is completely open to the greenhouse/conservatory was added at the same time. That tank receives natural sunlight but it also has metal halides and fluorescents. It's located in Bridgewater, Mass.

This beautiful reef aquarium is located in Adelaide, South Australia. Remember he's in the Southern Hemisphere, so South Australia is temperate, North Australia is tropical. He has SolaTubes connected to a skylight in his roof. His roof faces north toward the sun (Southern Hemisphere again). He uses some supplemental lighting. He has tons of photos in that thread but you can always cheat and jump straight to page 9 for recent photos.

[evilnewbie]

Evil,

How are you thinking of getting the sunlight to your tank? I've seen a place that pipes it in with fiber optic cables and I think they had great success.

If you just stick it in a window, I don't think you'll get enough direct sunlight on each piece of coral as they would get normally in nature. Plus depending on the window glass, there may be some tinting or filtering built into it. It would be a good supplement though.

I have my refugium/sump that gets some direct sunlight through a south-facing window...I have not seen any ill effects of that at all except I get algae growing in my CA reactor until I covered it with a towel. The stuff in my sump/refugium is growing quite well...haven't had it in there without the window, so I have no comparison.

Yes, I am actually thinking about "solar tubes" where sunlight is reflected internally and brought down to bear on a specified area... It seems like a very good idea and perhaps, superior to metal halides... I am not really worried about heat but I am worried about local sun weather... it seems most places don't get a lot of sunshine year round and perhaps the tank should be supplemented with metal halides during the winter months... I was just wondering if people out there were able to use sunlight during these winter months without metal halides with any success...

[reefhead728]

Where in sc are you from? Coast, midlands, or upstate?

[Doodaa]

It seems like a very good idea and perhaps, superior to metal halides...

I'm not a light expert, but it makes sense...corals evolved to use sunlight, so sunlight is what would be best for them.

Yes, I am actually thinking about "solar tubes" where sunlight is reflected internally and brought down to bear on a specified area... It seems like a very good idea and perhaps, superior to metal halides... I am not really worried about heat but I am worried about local sun weather... it seems most places don't get a lot of sunshine year round and perhaps the tank should be supplemented with metal halides during the winter months... I was just wondering if people out there were able to use sunlight during these winter months without metal halides with any success...

I don't know what the cloud cover is like where corals grow, so I can't really answer if the non-sunny days are bad. I do know, however, that even though it's cloudy, a lot of the higher frequency (blues and ultraviolet) light spectrum still penetrates the clouds.

Another thing to think about is that your tank is mostly shallower than where the corals are in the ocean and water diffuses a lot of the lower frequency light waves out (reds and yellows) so cloud cover and good solar tubes lighting your tank should be good. Are your solar tubes domed and magnified on the roof? That'll collect even more light to bring in.

If you do this, please start a thread and explain the equipment and process you are doing as I am quite interested in lowering my power bill ;)

[kevinpo]

Hello,
Several years ago (OK maybe 5) Anthony and I had the same talk late one night he said it was quite possible even at my northern latitude (47° 37′ 12″ N). So I set up a 40 gal breeder 12" or so from the window that receives 3 hours a day of direct sunlight in the summer. The test corals were M. digitata, M. capricornis, A. yongei, and P. damicornis. They were all moved from a tank with 400W halides that are about 16" deep and had intense coloration. That was in the month of August. By November the sun had moved so far south the tank was no longer receiving direct sunlight but just ambient light. I also had a 30W URI 50/50 bulb running 14 hours/day. At this time the corals were maintaining their color and growing at similar rates as before. By the end of Nov. they had all turned pretty brown and the growth rates slowed. By the end of Feb. the tank started to receive direct sunlight again and in about 30 days the color returned.

I was concerned that the side of the corals away from the window wouldn't receive enough light but it turned out to be unfounded. The front and back sides of the tank were kept clean. Although the sunlight was hitting the tank at an angle there was enough reflection off the front glass to keep the corals colored on the side away from the window. Even with AC the temperature would rise about 4F during the direct sunlight period due to the IR radiation. The maximum temperature reached was 80.9F. I did not try to cool the tank with a fan which would have kept the tank in the 77-78F range.

I have since removed the 30W light and replaced it with a 150W 14,000K metal halide. This keeps the corals colored year round. So IME it can be done even with moderate light requiring corals. I did not try high light Acropora like A. lovelli, A. austera, or A. cerealis.

Regards,
Kevin