Lighting = the tropics

[awestruck]

Curiosity question: Various experts say that the lights should be on 12-14 hours per day (excluding the lunar lights), with the metal halides coming on and going off during the times mimicking when the sun is shining its brightest. If you have really sophisticated lighting (which, unfortunately, I do not), do you ever have days when your lighting stays dimmer to resemble the occasional cloudy, rainy day? If Mother Nature creates days when photosynthesizing slows, should occasionally we be doing that too with our reef tanks? Or, does photosynthesizing continue at its normal rate even during cloudy, rainy days? Thanx for any response--I've only been reefing for 2 years and have a great deal to learn (hope the learning never stops!).

 

[Steven Pro]

There are some controls that will do this for you.

 

[Acroholic]

You know what...I have been reading numerous threads lately where someone believes he/she will better serve the tank environment by changing lighting on/off, or spectrum change etc. etc. to simulate more natural lighting conditions, IE cloudy days vs. sunny days etc.
After being involved in Hydroponics for numerous years, I have come to one conclusion. STABILITY & CONSISTENCY are the main factors in maximum growth and health of specimens propagated! Especially after growing multiple generations from the same genetic mother, showing even more growth and better health and more final product after each generation kept in exacting conditions.
A temp swing or a light outage will show a definite decrease in the quantity of final product...this IS quantitive!
We did however change light spectrum....using MH for growth till flowering and changing to High Pressure Sodium Bulbs thru the flowering process. And did have to change light cycle (less light during the day) to induce flowering. But once flowering was induced we upped the light cycle back to 18 hrs a day.
I firmly believe that by keeping a steady and consistent lighting schedule (which will also help keep our temp. consistent) will benefit our corals in the best possible healthy environment. This is of course if extreme growth and health are your main priorities.

Maybe I cannot compare the two.....I would be interested to hear more about this.

 

[awestruck]

Since I started this thread I obviously do not know what is "best". I probably do not even know what is worst aside from the very obvious. I just thought that perhaps there is some imperative reason (that which we may or may not know) why ocean life needs to take an occasional day of rest; of course, I am hypothosizing that synthesizing IS taking a bit of a rest during cloudy and/or rainy days. That thought could be totally silly in and of itself. Mr. Steven Pro responded that "there are some controls that will do this for you" (mimic cloudy/rainy day lighting). That is pretty cool. And again I am curious, how do the controls know when to schedule a day which resembles cloudy and/or rainy vis-a-vis a real cloudy/rainy day. Any thoughts or ideas would certainly be worth hearing.:thumbsup: And as always, peace.

 

[castorpollux]

its just reality versus perfection. you will get more bang for your buck with your lights on consistent timing and power.

 

[Steven Pro]

To maximize growth, I would leave the lights on full time. But there is an arguement to be made that to induce spawning we might need to simulate variations in temperature, lighting, lunar cycles, etc.

 

[awestruck]

Thank you to those who have responded. I guess we just keep doing the best we can. As always, peace.

 

[T Man]

I see LCD arrays in the future, programmed for all weather and lighting conditions including lunar cycles and the four seasons.....Just waiting for it to come to fruition. TinMan

 

[Steven Pro]

<a href=showthread.php?s=&postid=8454354#post8454354 target=_blank>Originally posted</a> by LU359TINMAN
I see LCD arrays in the future, programmed for all weather and lighting conditions including lunar cycles and the four seasons.....Just waiting for it to come to fruition. TinMan

The PFO Solaris fixture does that.

 

[Donw]

<a href=showthread.php?s=&postid=8445900#post8445900 target=_blank>Originally posted</a> by awestruck
Since I started this thread I obviously do not know what is "best". I probably do not even know what is worst aside from the very obvious. I just thought that perhaps there is some imperative reason (that which we may or may not know) why ocean life needs to take an occasional day of rest; of course, I am hypothosizing that synthesizing IS taking a bit of a rest during cloudy and/or rainy days. That thought could be totally silly in and of itself. Mr. Steven Pro responded that "there are some controls that will do this for you" (mimic cloudy/rainy day lighting). That is pretty cool. And again I am curious, how do the controls know when to schedule a day which resembles cloudy and/or rainy vis-a-vis a real cloudy/rainy day. Any thoughts or ideas would certainly be worth hearing.:thumbsup: And as always, peace.

The lighting is the easy part, I could do that now. I just dont think there is any real data to support whether or not its a benefit.
Ive got mine set on a two hour very slow incline and decline but thats for my benefit not the corals.
If you find some data let us know, I'll be happy to try it out for you.

Don

 

[BeanAnimal]

My setup (when I get around to finishing it)... will simulate the solar and lunar cycle for any desired location on the planet. As with Don's setup, this is for my benefit more than anything. I would guess that it may make the fish more comfortable having a sunrise and sunset as well.

Bean

 

[samtheman]

<a href=showthread.php?s=&postid=8462140#post8462140 target=_blank>Originally posted</a> by BeanAnimal
My setup (when I get around to finishing it)... will simulate the solar and lunar cycle for any desired location on the planet. As with Don's setup, this is for my benefit more than anything. I would guess that it may make the fish more comfortable having a sunrise and sunset as well.

Bean

Because of the angle of refraction of water, there is not a sunrise or sunset under water. Mimic away.

 

[Steven Pro]

<a href=showthread.php?s=&postid=8463021#post8463021 target=_blank>Originally posted</a> by samtheman
Because of the angle of refraction of water, there is not a sunrise or sunset under water. Mimic away.

Huh?

 

[samtheman]

As the sun sets, it passes the angle of refraction of water. Once past that angle, almost all of the light striking the water is reflected. So in the morning and evening the sun just kinds of turns on and off, rather than changing slowly as it does in the atmosphere.

 

[BeanAnimal]

<a href=showthread.php?s=&postid=8463021#post8463021 target=_blank>Originally posted</a> by samtheman
Because of the angle of refraction of water, there is not a sunrise or sunset under water. Mimic away.

What are you talking about sam? As the sun rises, the ambient light over the water increases. During mid day with the sun is at its peak, the light will be the brightest. As the sun begins to set, the ambient light will become dimmer. This has NOTHING to do with "the angle of refratction".

We are not talking about the angle at which light strikes the corals or the reef. We are not talking about shadows or the direction the light is coming from.... we are simply talking about the amount of available light.

I think if you step back and think about the situation, you will see that the light available underwater will rise and fall with sunrise and sunset. The light pentrating the ocean does not go from "on" to "off" at some specific point in the day like it does in our tanks. Instead it is a gradual process. That gradual process is what myself and others are attempting to mimic....

Bean

 

[Acroholic]

In my diving experience..there is definitely a gradual increase/decrease in ambient light due to sunrise/sunset.
I turn my lights on/off one at a time in 1/2 hour increments...I.E. moonlight to VHO to 1st MH to 2nd MH to 3rd MH and reverse this turning lights off.....
This is not done to simulate sunrise/sunset but rather to keep from shocking my corals with a blast of 1500 watts of light in an instant second.
What I was describing in my earlier post..was that for instance:

We had a lighting problem for a day which no lights were turned on for a normal 18 hour light cycle. Now, our plants just didn't lose that growing period for one day...it took over a week before the plants were growing at the rate per day they were before the light outage. SO, basically what I am trying to say is, without one day of light, they actually lost maybe 5 or 6 days of growth. This is what I can see happening with a lighting system that tries to simulate as a cloudy day....I think you are doing a lot more harm than you think in regards to growth....you are not just losing that one day of growth, you are actually losing many days of growth...now compound that with attempting to simulate multiple cloudy days randomly.....I don't really see how anything could properly grow in this type of lighting environment. Just my 2 cents.....

 

[Zen Reeferer]

With the increasing popularity of LED systems, any chance they will come up with something like the
Fremont Street Experience in Vegas, (click on one of the Fremont St. Experience video links) for our tanks?
Granted it's huge (actually, it's a canopy over entire street, 1,400 ft. long, over 12 million synchronized LED modules)
But could it be (effectively) scaled-down to our tanks footprint? Could it work, to keep corals happy?
How cool would that be to program-in the sun, occational clouds, hurricanes, waves, predators, sunset/sunrise...?
If possible, it would definatelly be spendy...but wow, what a show, lol.
Ok...no more coffee for me today, lol...
...James

 

[Donw]

I dont buy the no sunrise or sunset underwater thing. I really cant justify the the plant comparison either. Not that I know alot about plants but as with plants there to many different lighting requirements in a reef tank. We pack our tanks with such a variety just like we do our flower beds. Some need more light than others. Heck even my front and back yard has two different grasses for two different light levels.
I think it would be a cool experiment if someone had some lighting data maybe sunrise and sunset time over a location such as the GBR.
The mechanics of the lighting is the easy part, the data is going to tough to figure out.

Don

 

[badgers034]

Or, does photosynthesizing continue at its normal rate even during cloudy, rainy days?

Now, somebody correct me if I am wrong, but I dont think that corals are autotrophs (make their own food). Also, about your question, yes the dark reactions of photosynthesis will occur because they are powered by ATP, so they do not need sunlight.

 

[BeanAnimal]

Don... there is no need to buy it... Sam (as he sometimes tends to show) has no idea what he is talking about. The light levels under water will follow the same light levels that are available above the water.

As far as sunrise and sunset data... that is readily available at NOAA and many other webstites. I already wrote the software for my PC based controller. It takes the longitude and latitude and calculates sunrise and sunset. I did not go as far as looking into the actual light levels for the different parts of the day... I am sure it is not linear with respect to time....

Bean