Dawn/Dusk Lighting

[Witfull]

in order to not hijack a thread further...lets continue the discussion here.

Originally posted by Dingo
I run a 14 K XO bulb, which doesn't really address your colors, but I am pleased with the colors in the tank. It's already been said, but the only reason to put in actinics is if you think they look cool. I have none, and the corals could care less.

Originally posted by Witfull
the one thing i do like about dawn/dusk is that it tells the fish its time to go to bed,,,when the halide click off, i see my fire fish begin to hover over the rock they call a bedroom. they will flitter over it and one by one they settle in for the night. also i have seen to many fish get injured by getting spooked by the lights suddenly going out and flaying around the tank trying to hide.

this may not be a problem in a well lit room where outside lamps are on, but my tank is in a room where the only light on when the lights shut down is the TV and computer.

also, nowhere in nature does the sun go from high noon to midnight black in .000000002 seconds. i have no scientific evidence to support that fish benefit from gradual lighting changes, but from a purely observational point there must be merit.

Originally posted by wooddood
i'll have to agree with witt here, the ocean does'nt go dark all of the sudden and are'nt we all trying i mimmick mother nature in our quest to run a successfull reef enviornment? i personally like the dawn dusk effect and its eye appeal to my reef and its inhabitants, it has to effect the fish like dave mentioned earlier. and i have to believe it does affect some corals to some degree if a dawn dusk affect is'nt used at all, sorry but i'm not taking the chance to find out in my reef. all i can say you'll have to show me it does'nt matter. jmpo.

dave.

Originally posted by ReefLady
From what I've read, the moment that dawn breaks over the Indo-Pacific reef, the lighting is x times more powerful than any halide system on our tanks.

If we were truly trying to simulate a natural habitat, we'd have cloudy days, rain, hurricanes, and natural predators in our tanks.

In any case, there are hundreds (thousands?) of reef tanks out there lit with no dawn/dusk, and with no ill effects.

Originally posted by wooddood
ok that may be true to an extent but i know you do and i do, maybe its a trend like a dsb. all i know is i'm not going too nor am i ever going back to a dsb either. but thats this hobby everyone does things different in thier reefkeeping and always will, but thats just this hobby and the way it is. not trying to argue the fact just stating my point . if it works for some people then i'm happy for them. good luck mattie. i really mean that.

dave.

what do you think,,,know of any studies...lets talk!

[cheeks69]

This was from another website but I think it applies:

"As anyone who has dived at sunrise on an equatorial reef will tell you, light reaches high intensity after sunrise incredibly quickly - within minutes - so reef fish and corals are well used to the "lights on" and "lights off" syndrome: it happens in their natural habitat!

Lastly, actinic lights have much lower lumens per watt than, say, 10,000K lights. Put simply, watt for watt they are DIMMER, not brighter. The shorter the wavelength (the higher the K number), the lower the lumens per watt. A 20,000K 250W halide delivers significantly less lumens than a 5,600K 250W halide. And only deep ocean corals will grow in pure actinic light."

[NaH2O]

Hmmm....IMO, there is more to it than just the lights on and off. Don't forget the gravitational pulls from the moon depending on where it is in cycle....those are forces we cannot replicate with our lighting.

[Witfull]

here is a thought, as stated by teri and robert, the sun rises quickly after the sun rises, but there is pre dawn light and just as the sun is rising isnt there gradual brightening same as sun down, it is still light out.

and as for rainy days and storms and such Teri, i have them its called maintainence day....hurricanes,hmmm is that the day i rip it apart and rearrange everything?....LOL

[NaH2O]

Certainly we make a "storm" when we are doing maintenance, but it by no means is a recreation of what's happening on the reef (not implying that you are saying that...just stating). There are things that we cannot match like cool water currents, tides, etc....it just isn't the same thing.

[cheeks69]

Originally posted by Miniatus

I read an article a few years back,and it stated that 90% of coral reef are on or near the equator, heres the kicker there is no true sunrise or sunset on the equator. Basically the sun is there and then its gone. So then low light in the morning building up to full sun then slowly sinking at night is a bunch of bunk. I wish I could find that article,it saved me a few bucks when I was going to buy a dimmer , anyway My coral don't go bonkers when they get full lights in a matter of a few seconds. JMHO.

I believe that especially Halides coming on all of a sudden can startle fish. When I received fish thru the mail It was always mentioned in the directions that come with the packaging to turn off lights otherwise it would shock the fish so I think there's some merit to at least have some sort of weaker light come on to help the fish acclimate JMHO

[Witfull]

first refference i have found. ill keep looking.

from here

In the native habitat of our charges, namely on the tropical coral reefs, day and night each measure 12 hours. Transitional periods to day or night - dawn and dusk - are comparatively short, only about 30 minutes....It has been proved to be advantageous to start and end the day light phase with the aid of blue light emitting fluorescent lamps (400 - 470Nm).

[Witfull]

another refference on sunrise and light penetration on reefs.

here

The sun begins the day’s journey toward its zenith and the clear ocean water begins to assume the color of the reflected light. What was once a black ocean turns to gray; when the sun is higher, the sea will turn to blue. The morning sun falls upon the coral. Within the tissues, the zooxanthellae awaken and begin to use the small amount of energy. They begin to produce small amounts of oxygen through the process we call photosynthesis. Radiant energy increases as the solar disk climbs higher in the sky. The photosynthetic pigments within the coral’s zooxanthellae work harder and produce more oxygen. At some point, the oxygen produced by the zooxanthellae will meet their and the coral’s respiratory needs and they will no longer gather dissolved oxygen from the water (Scientists would say that they have reached the Compensation Point)..... As the sun begins its slow march to dusk, less energy penetrates the warm ocean and once again the coral’s zooxanthellae photosynthesize at a rate proportional to the amount of light falling upon them. At sunset, just as earlier in the day, they will again reach the Compensation Point and begin to extract oxygen from the water in order to survive. They will continue to do so until the next morning’s dawn and the process will begin anew.

[Reef Geek]

I can't speak for what the sun does below the ocean, but here on its surface it beats down mercilessly from about sunrise +1 hour to sunset -1 hour. At least 10 hours of extremely intense light. Why can I say this?
Current position: 0N 154W

[mojoreef]

I would have to say that the use of dawn and dusk lighting would be closer to what occurs in natural habitats. Most fish that inhabit the reef are hiden with in the rocks and corals, this alone will not allow light to all of a sudden blast onto the reef. Having said that I dont think its an absolute for either corals and/or fish but it is definately not something that would hurt them.


Mike

[ReschM]

I don't have a tank yet but certain things are given on this planet. First, the earth rotates, allowing gradual increase and decrease in lighting. Second, out in the ocean where reefs are located, there are no trees, mountains or man made objects to block the suns rays. So yes there is a gradual increase and decrease of light but the change is much more sudden then what we are used to, Maybe not as sudden as flipping a switch but fish around the world have survived the light on, light off life style for years.

[Stevenmi]

I know two things for sure on this topic.

1.) If I was a fish, and someone woke up from the blackness of the morning with with an immediate blast of 500w in my eyes...I would be pretty pissed off...until my eyes adjusted, and i got my bowl of captain crunch(or the marine equal). Thankfully most tanks get "room light" before main lights are turned on.

2.) Most living creatures react with discomfort to drastic change...We as reef keepers try all we can to keep a stable enviroment, salinity levels, temp, ph...etc...Those that are more sucessfull in my observations, try to limit extreem sudden changes to the nth degree. remeber..light is energy and energy sets off a host of chemical and then biological processes.

Steve

[Snooker00]

Since ya'll are on the subject, would you have your timers set so that the lunar lights come on before the MH go off?
Steve

[Witfull]

my night like it a light sensor,,,when the lights go out,,the nightlight comes on

[cheeks69]

I have it set up that the halides go off at 7:30pm then the actinics at 9:30pm and then moonlights come on.