Natural sunlight?

[gmerek2]

Does anyone keep their tank in front of a window and get direct sunlight? Would this cause any problems? The sunlight reflects off my floor and my corals seem to love it.

[Orion]

You may get more algae growth, and the heat transfer may warm the tank up a bit much.

[Enkay]

Yes, I do. I get the morning sun on the tank and the corals love it. I dont think there is any substitute to sunlight. 

 

But as Orion stated, you do get more algae. So as long as you are ready and able to clean frequently and get rid of the algae, I think it is great that the corals get natural sunlight.

[gmerek2]

Sounding like 1-2hours of good ol fashion natural sunlight would be a great treat for the corals and fish but anything more could cause algae and heat issues. How would sunlight cause algae growth? too much light? different spectrum? I bet neighbors would love the tank in the window I can see mine peaking in as they walk by

[Neto]

I  used to have a 10 gallon next to a window and it didnt do so well.. After moving it away from the window it did... I assume it was getting too hot or maybe I was dealing with some other issue.. An ac vent was next to it as well

[Origami]

Temperature control becomes, I think, the biggest issue that you need to contend with with a tank that's near a window. Sunlight is great, but just like a shallow wading pool at your local community pool, the water can quickly warm. So you need to think that through first before committing to situating a tank too close to a brightly lit window. In your situation, it seems like your tank is receiving reflected light so maybe it's not right at the window, but maybe on the far side of the room. In that case, temperature control may be less of an issue. Natural light is great and free, too.

[matt]

My tank gets some indirect light in the morning and I 'think' my corals appreciate it. I do get a bit of algae on the back glass...perhaps from the sun's lower K rays or perhaps it's the room lamps' incandescent lighting that we use in the evening. The tank is positioned mostly perpendicular to the south/southeastern windows though I have a good bit of tree-cover there as well.

 

My tank wakes up to this natural light hitting the front side while my display flow is still at nighttime levels. I crank up to daytime flow (mid-morning) and then I fire the led actinics and t5 bulbs lighting the back half of the tank (late morning), followed by the front half t5 bulbs a bit later (mid-day). I do a similar shutdown, minus the sunlight factor. Fish seem to like these transitions too.  

[s2nhle]

My dt get indirect sunlight on the left hand side. I did not get algea but I do have a lot of purple coraline on that side compare to right hand side. I also got a household fan on the  right and it is on when the light are on.

[gmerek2]

I would think with the sunlight reflecting off the floor is a benefit since it can hit the rocks/corals at a different angle. This could possibly give corals sunlight "where the sun don't shine" I have seen some birdnest with a huge canopy and not a whole lot can grow under it since our lighting systems can only do top down angle. My tank gets about 4 hours indirect sunlight. Is it enough to support a coral in the shade? Probably not but I can see the corals open and expand before my LEDs kick on. Neat stuff love this hobby.

[jaddc]

Temperature control becomes, I think, the biggest issue that you need to contend with with a tank that's near a window. Sunlight is great, but just like a shallow wading pool at your local community pool, the water can quickly warm. So you need to think that through first before committing to situating a tank too close to a brightly lit window. In your situation, it seems like your tank is receiving reflected light so maybe it's not right at the window, but maybe on the far side of the room. In that case, temperature control may be less of an issue. Natural light is great and free, too.

 

Absolutely. Here is what I'd consider in addition:

 

1) Temperature. Not much of a problem if you have a good chiller and heater working together to maintain a stable temperature. You could also use a screen that greenhouses use to control the heat and light.

 

2) PAR intensity. If you do any SCUBA, then you know that the ocean absorbs a lot of light rather quickly. So many deep corals are exposed to less intense light and they have adapted to it. Shallow corals of course love the higher intensity. But our tanks are not deep enough to replicate this gradient. The best we can do is shade a deep water coral as much as possible. Corals adapt quite well over time and so this works for the hobby. Modern lights are nice because we can control the intensity and also arrange the lights to have shadier areas of the tank.

 

3) PAR spectrum. The divers amongst us can tell you that as you go deeper, everything just looks blue. The ocean water absorbs long wavelength (green to red) light strongly. Blue is pretty much the only wavelength that penetrates deep into the ocean. Because of this, most deep coral (zooxanthellae) respond well to blue light (that's why we love the actinics for the "pop" of fluorescent color). So for our shallow (relatively) reef tanks, sunlight would deliver more green to red wavelength light than the corals would normally be exposed to in the ocean. Is this a bad thing? Not so much for the corals, but many species of algae love long wavelength light found in shallow waters and thrive on it. Again, to replicate this phenomenon, our modern lights have a spectrum that is well tuned (or tunable) for a reef tank and most reefers tune down the red to avoid algae. It is also why we light our refugiums with broad spectrum lights (like flood lights) to encourage algae growth.

 

All that said. Sunlight is free and there is no reason not to use it. Greenhouses are used to house reef tanks (especially for suppliers -- like Dr. Macs) very successfully. All one needs to is acclimate, acclimate, acclimate. Also be prepared for increased algae, but like all algae outbreaks it can be controlled.

[taiscici]

This guy on RC http://www.reefcentral.com/forums/showthread.php?t=2040499&page=24 uses natural sunlight for his reef tank. His tank looks so natural and bright, also I don't see any algae problem.

[Enkay]

Great thread. Thank you for posting the link. Will probably go through the entirety of it when I get the time. Would be interesting to know how he combats algae for sure.

[PK3]

The natural sunlight discussion reminds me of one of my all time favorite tanks.  http://reefkeeping.com/issues/2008-12/totm/

[jaddc]

Great thread. Thank you for posting the link. Will probably go through the entirety of it when I get the time. Would be interesting to know how he combats algae for sure.

 

He probably combats algae the same way a non-sunlit tank stays algae-free. Hard work, know-how, and the addition of minimal nutrients.

[zygote2k]

The natural sunlight discussion reminds me of one of my all time favorite tanks.  http://reefkeeping.com/issues/2008-12/totm/

+1. Very nicely done tank. It's been one of my favorites for some time.

[gmerek2]

Thanks guys I learned a lot more than I bargained for. Didn't know that about reds in refugium and blues in the ocean. I need to get some more reds in my refugium I would rather have the algae there eating away than in my DT.

[jaddc]

Thanks guys I learned a lot more than I bargained for. Didn't know that about reds in refugium and blues in the ocean. I need to get some more reds in my refugium I would rather have the algae there eating away than in my DT.

 

I think every reefer has said that at one point. :-)

 

Just to be clear, you don't need to turn your refugium into a red-light photography dark room. People just use regular white light bulbs with a lower Kelvin rating (<7000). That category includes fluorescent and incandescent lights, which emit a more balanced spectrum. Luckily, it is as cheap as it is effective. The DT lights are generally higher Kelvin (more blue) to replicate the effect of the ocean water on the sunlight.

[jimlin]

 

here is a picture of a sps dominated tank that uses natural sunlight at the Waikiki Aquarium. natural sunlight works but is rather unreliable due to seasonal changes, clouds, rain and such if one were to use sunlight as the only source of lighting for their aquarium. i kept my 75 gallon tank next to a window for a short period a couple of months ago before i moved. i had crazy temperature swings during that time. now that i have a chiller, i may move it by a window once we get situated just to see how it does.