To moonlight or not to moonlight?...that is the question

[SouthBayPhoto]

Howdy all!

I was wondering if any of you have put in the moonlight LED's in your reef and/or FOWLR tanks?

I currently have one on my 46 (it's a 5 LED one that is right in the middle and lights up all 36" of my tank nicely) and I think it's great to be able to watch everyone movin' around after the lights to out.

I'm thinkin' about putting some on my 90 build. If I'm going to do it, might as well do it when I order my T5 retro kit.

Sooooo...I'm wondering what everyone's thoughts and/or experiences are with moonlighting.

Is it actually beneficial? Is it a waste of time? Is it a fad? Is it a bad thing to do? etc...

Thanks!

[charlie]

Mostly for aesthetics Mat. I have read that sometimes clams will spawn with them, but I don't know if that is directly related to having moonlites or not. HTH

[greenbean36191]

There's very little evidence that animals in the wild are responding in any positive way to the actual light of the moon. We know essentially zip about the benefits of moonlight in the wild, so it's pretty hard to say what the benefits would be in captivity. However, moonlights in the hobby tend to be nothing at all like moonlight on the reef. Not only is the color of the artificial moonlights generally much bluer than real moonlight, it's usually tens to hundreds of times as bright. A good rule of thumb is that if you can read by the light coming from the tank at night then it's too bright to simulate moonlight. Keep in mind that our critters are much more sensitive to blue light then our eyes are, so while it may look dim to you, it's brighter to them. What, if any, effects this overillumination might have aren't clear since it's not a problem in nature so has been essentially unstudied.

My tanks never had moonlights, and until there is some evidence suggesting benefits of moonlight they never will. When used properly to simulate moonlight, they don't really add much to aesthetics. As they're typically used in the hobby I can only imagine their real impact on the animals is a negative one, though probably small.

[pearl_aqg]

Aside from organisms that may need cues from the lunar cycle to spawn, night lighting is mostly for your viewing pleasure. If recreating phases of the cycle is your goal, you'd theoretically need different levels of lunar lighting as moonlight will grow brighter/whiter and darker through different phases. There are lunar lights (I'm thinking of the Current modules) that attempt to recreate this with blue, white etc but you'd probably be able to accomplish this with a single light on a dimmer switch as well. Color of moonlight is likely not a factor, while intensity would be.

I have seen it written on other reef sites and blogs that lunar lighting is not harmful, but I'm unaware of any research that definitively says one way or the other. Most resources seem to agree that at the least it's a nice way to view your fish's nocturnal behavior, realistic or not, and low intensity lunar LEDs shouldn't disturb or disrupt the processes in your tank. Of course, if you install them and your fish start showing signs of stress, take em out!

[art_of_war]

interesting.

[Ninong]

This topic keeps coming up over and over again.

Unless you are using a computer to control the intensity of the "moonlight" to replicate the phases of the moon and to turn your "moonlight" on and off in synch with moonrise and moonset, you don't have a moonlight. You have a nightlight over your aquarium.

In previous threads I have posted a copy of Steve Tyree's chart of the intensity of moonlight striking corals during each day of the 29-day lunar cycle. Except for full moon and a few days before and after, the intensity is really, really dim. And, of course, the moon rarely rises just after sunset and sets just before sunrise. That only happens over tanks with nightlights. Tanks with a moonlight will sometimes have the moonlight on at the same time as the regular daytime lights and sometimes the moonlight will be off completely (new moon).

Moonlight, obviously, is nothing more than reflected sunlight. The only reason it appears slightly bluish to human eyes is because of our lousy eyesight when it comes to registering dim light.

If you would like to have a nightlight over your aquarium, don't over do it. I don't think it would hurt to have a very weak nightlight over the tank. It might confuse the hell out of the tank's inhabitants, especially if it's too bright, but I don't think it will cause any harm. They certainly aren't going to mistake it for moonlight if it's on every night, all night.

If you would like to read a detailed explanation of the role of the full moon in the annual mass spawning of coral reefs, check out this article. You will see that there are several factors that determine the exact date of the annual mass spawning. The mass spawning of the Great Barrier Reef sometimes begins four or five days after the November full moon and sometimes it's four or five days after the October full moon. The reason it varies is tied to water temperature. If the water temperature is warm enough, it will happen in October, otherwise it will wait until November. Some years there are split mass spawnings, both October and November.

Why does it happen four or five days after a full moon? Because that's when there is a neap tide. The tide during a full moon is the strongest tide. The tide four or five days later is the weakest tide. Why do corals, clams, polychaetes, etc., want to spawn during a weak tide? Because it allows more time for the mixing sperm and eggs to become fertilized. Why do they all spawn at the same time? To overwhelm the predators (fish) with more gametes than they can consume. How long does the annual mass spawning of the GBR last? They don't say so in that article but I believe it's either three or four days. I remember that the polychaetes spawn on the last day. I believe the clams spawn on either the second or third day. I think I have seen this on the various Nature channels at least half a dozen times by now.

Check out that article. It's pretty interesting stuff. Notice that the reefs off western Australia spawn at an entirely different time of the year.

P.S. -- I copied the following from a post of mine back in June 2005:

Steve Tyree covered moonlight intensity in an article he wrote back in 1992. He evidently covered it in even greater detail in another article in 1994 because his artificial moonlight in the aquarium charts have been copied in Fossa & Nilsen's The Modern Coral Reef Aquarium, Volume One on pages 201 and 202. The maximum at full moon would give a reading of 200 lux incident on the surface of the corals. Most of the month it would be much less intense than that and for a third of the month it would be less than 40 lux. In fact, for eight days near new moon it would be less than 20 lux.

You can duplicate those conditions with one or more (depending on the surface area of your tank) 25w blue incandescent lamps controlled by a computer, such as Neptune Systems Aquacontroller, that dims the lamps to replicate natural moonlight intensity depending on the phase of the moon. The controller also turns the moonlight on and off in accordance with natural moonrise and moonset schedules, which means that your moonlight's photoperiod will vary each night and it will even be on during the daylight part of the time.

If you don't have a computer controller for your moonlight, just check with the Naval Observatory's handy little moonrise and moonset calculator and reset your timer every day. Oh, and you would need to have a dimmer, too, so that you could adjust the intensity based on the appropriate phase. And a luxmeter to measure the intensity.

(I wrote that before LED lamps were in common use for reef aquarium lighting. PFO claims that their new Solaris LED fixtures are able to replicate moonlight intensity and rise and set times via an onboard computer.)

P.P.S. -- Sexual reproduction in many animals is tied to the lunar cycle. Our ancestors' reproductive cycle was closely attuned to the lunar cycle back when we were nocturnal, many millions of years ago. The reproductive cycle in female humans is still on the lunar cycle.

[Ninong]

For those with unlimited funds, it's now possible to come fairly close to replicating the natural environment in a reef aquarium. Naturally we can't ever replicate the dillution factor of the ocean or the intensity of water movement but we can do the following:

We can control the water temperature to duplicate seasonal water temps. Many hobbyists do this already. I don't know of any of them who bother with diurnal fluctuations but many advanced hobbyists do adjust the water temperature to match natural conditions. You have to exercise a bit of caution here because you really don't want to duplicate the extremes. However, you can have your computer set to vary your water temperature from a high of 83 degrees Fahrenheit in the "summer" to a low of 78 F in the "winter." I wouldn't go much higher than 83 F even if natural water temps do go higher than that.

Here's a look at what the water temperature is in Fiji (readings taken at a depth of 30 feet from sensors in six different sites):



Don't try to match those highs in a captive reef aquarium. Stay below 84 F. Don't go below 78 F. You might have one month of the year set for 78 F and a couple of months set for 79 F. Most of the months you would want to be set between 80-83. Use your imagination.

Then you would want a fancy light fixture setup that allows you to replicate daily and seasonal light intensity variations. These have been available for several years now. And, of course, you would absolutely want a moonlight with correct computer control to replicate natural moonlight.

The Tunze Streams (the variable electronic models) come with a tidal duplication program that would help you simulate tidal cycles. Four of those with their computer would set you back about $1,687.

I don't think it would make much sense to bother with all of this unless your aquarium was at least 500 gallons. Plan on a budget in the $100,000 range.

Good luck!



P.S. -- Be sure to post pics!

[charlie]

Very interesting post Ninong, thank you!!!!

[SouthBayPhoto]

Cool...some darn good info, as always, Ninong. I appreciate it. Sorry to bring up the subject again. I should have searched for it first. DOHHHH!

I'm only using my night light (currently on my 46g) for aesthetics. Just so I can sit and watch the creatures after the main lights go out. I was considering doing it for my 90g, but if it might be too bright or confusing, then maybe I shouldn't.

I was actually considering the "Current USA" (I think that's the name of them) lunar lights. I was going to put 3 of them, spaced evenly across, in the 4 foot canopy. If I remember correctly, they are just under 1 watt a piece.

I don't want to stress out my inhabitants at all...I know no one can make the decision for me, but that was why I was asking what everyone else did so I can try and make an informed decision.

Thanks again for the info!

[Ratpack]

My Current light fixtures came with LED moonlights and I have them on when the other lights go out and it is real nice to be able to see at night although it is still hard as it isn't real bright. I do have a set of the Current Lunar Lights for the 75g. I have the one main and one addon so each 2 foot section will have a light. The ones I have are the blue ones. I tried them out on my current tank and it was neat. My LPS glowed green when I aimed it directly at them. But like others have said, if there is real data to support them harming anything, I won't use them. They are strictly for night viewing in my case.

[SouthBayPhoto]

Tim,

Those are the exact ones I'm looking to buy. I was just going to put three of them across my 4 foot tank. I figured that should work out fine.

[zhenya]

I bought lunar tracker from theLebos.com, it comes with their own led lights and they dim and get brighter to follow the moon cycle. However, I too think the lights are too bright, so I kind of put them behind the reflectors and my reef gets only reflected light from bouncing ont he reflector's back surface. Kind of weird, I think, and way too much trouble to have it.
I definately can;t read by them...

[charlie]

How far off the water surface are your lites Gene? Is there a chance you could get a pic of what the tank looks like with them on?

[zhenya]

How far off the water surface are your lites Gene? Is there a chance you could get a pic of what the tank looks like with them on?

I would say about 14" off the surface of water and few more inches from the actual structure and corals on it.

Sure, I can take the shot but not sure if it will come out right. You can hardly see into the tank with them on, although some days it is brighter and some days it is almost completely off. So, I'll check tonight if I don't fall asleep before that.

[charlie]

I would say about 14" off the surface of water and few more inches from the actual structure and corals on it.

Sure, I can take the shot but not sure if it will come out right. You can hardly see into the tank with them on, although some days it is brighter and some days it is almost completely off. So, I'll check tonight if I don't fall asleep before that.

Are you perhaps reffering to that 1 pic in your thread?????? Probably gonna have to use a tripod for the prolonged exposure. That alone might put one to sleep.

I might have to take a look at that system you have, sounds like a fun thing to play around with.

[zhenya]

Are you perhaps reffering to that 1 pic in your thread?????? Probably gonna have to use a tripod for the prolonged exposure. That alone might put one to sleep.

I might have to take a look at that system you have, sounds like a fun thing to play around with.

Which one of the pix you are talking about? There are so many of my pics in the threads I forget which ones I posted after a few days.

Those things are fun to play with but I agree with greenbean, there isn't anything conclusive that would suggest that it helps anything in the aquarium. I have it for fun, like you said, but those lights of mine no where near enough to see anything in the tank at night time. I still have to use bright flashlight if I need to check on something inside the tank, or I turn the room lights on. I hate doing it because it wrecks havoc on the animals, though.