Photoperiod too long?

[ps2cho]

So the default photoperiod on my Photon 24s start at 7am and go to moonlights at 9pm. They ramp from 0 to 40 peak then back down.

 

Is that OK or should I consider shortening the time on it?

[NanaReefer]

14hrs of lighting + moonlights. Tad long IMO. I'd say 10-12hrs max

[CronicReefer]

The average amount of daylight per day can range from 10 hours to 14 hours depending on the season(unless you live at extreme north or south longitude). I try to keep mine in sync with the time of year.

[farkwar]

The average amount of daylight per day can range from 10 hours to 14 hours depending on the season(unless you live at extreme north or south longitude). I try to keep mine in sync with the time of year.

12:12 is typical for the equator. From where many of our animals originate..

 

 

 

[lynxer]

Im on 12:12.

 

My whites are on from 11-4 (5hours).

 

 

[jedimasterben]

12:12 is typical for the equator. From where many of our animals originate..

Not that close to it, usually. The Great Barrier Reef is pretty far away from it, as is the Caribbean and basically anywhere that isn't Indonesia. 'Typical' is anywhere from 11 hours in the winter to 13 hours in the summer, and averaging out to 12.

[farkwar]

Yup, 10 degrees North or South will give you approx 11:13 at the Solstice, 12:12 at the Equinox; etc.

 

 

My blue tang is in a tank thats lit 8 am to 8 pm, she starts looking for bed at about 6 now. The tank does get hit with natural sunlight, more in winter because the Sun is lower. I think shes take cues from it, or could be internal. It was weird behavior when I first noticed it.

 

Im going to change start and stop time after Standard Time kicks in.

[Nano sapiens]

12 hrs at the equator is correct, but consider that the first hour or so at dawn and then the last hour at dusk hardly penetrates the water surface or has much intensity when it does.

 

I've been using 10 hrs for the last year and everything is fine which also saves a bit on electricty costs and emitter life compared to using 12 hrs.

 

Corals are adaptable, so 10 -12 hrs should be fine.

[ps2cho]

I'm wondering if that would influence growth rates since some of my SPS haven't grown much. (Namely my Red Planet)....but maybe its them filling the plug where I glued onto the rock first before growing outwards?

 

I will do a transition to 12hr period either way!

[CrazyEyes]

I run my lights much more intense over my zoa tank for 6 hours opposed to less intense for longer and so far it seems to be working out well.

[Hart24601]

I don't concern myself much with photoperiod unless the PAR is really high for the daily light amount. I mean nothing else is natural in my tank, why should the light length be? I vary it for a change of pace and never notice any difference at all.

[farkwar]

12 hrs at the equator is correct, but consider that the first hour or so at dawn and then the last hour at dusk hardly penetrates the water surface or has much intensity when it does.

 

I've been using 10 hrs for the last year and everything is fine which also saves a bit on electricty costs and emitter life compared to using 12 hrs.

 

Corals are adaptable, so 10 -12 hrs should be fine.

Im not very worried about that.

 

I have two Kessils over a tank that gets some direct sun from about 7am to 830am. That sunlight at 7 in the morning is far more intense than the Kessils at full intensity. And I am way North, same with my Sun, than our corals can grow. That is to say the Sun at my longitude at 7am is far less intense than that Sunlight at 7am at the equator or 10 degrees north or south of it.

 

 

 

Photoperiod and intensity is far more important if you are trying to breed fish and inverts or reproduce coral by sexual means. Growing and propagating corals happens in a far larger window of error.

 

There is a Martin Moe lecture from this years Macna on Youtube that discusses all this, its on the BRSTV Channel.

[farkwar]

I'm wondering if that would influence growth rates since some of my SPS haven't grown much. (Namely my Red Planet)....but maybe its them filling the plug where I glued onto the rock first before growing outwards?

 

I will do a transition to 12hr period either way!

 

I have seen that Red Planet behavior in other tanks.. One was where the plug was on the back wall. Little 2 cm nubbin with a 15cm circle of encrustation around it, growing more like GSP than an acro.

 

I have slow growing acros growing much faster than my red planet(mine is like yours). Blue fast growing acros putting it to shame.

 

I have a couple volunteers starting on the encrusting part, though.

[Hart24601]

Interesting that at a bit over 500PAR for 12 hours exceeds the daily amount of light in a tide pool, and those would be some shallow corals 2" underwater! Funny when you search old posts it was only a couple of years ago you saw this statement all the time when discussing light and PAR, "We will never be able to match the intensity of the sun in our aquariums".

 

http://www.advancedaquarist.com/2013/9/aafeature

 

Of course sunlight has a decent amount of green that adds to PAR but not much to PUR, so really our tanks get much more PUR (at least most LEDs) than the PAR would indicate.

 

http://www.advancedaquarist.com/2012/10/aafeature

[farkwar]

Intensity is a very much a factor of distance, the Inverse Square Law.

 

 

Just for memory's sake thats roughly...

Double the distance, quarter the intensity,

Halve the distance, quadruple the intensity.

 

 

If that 500 PAR light is 8 inches above the water (that PAR number is for the very top of the rank, of course).

 

Moving that 500 light 8 more inches above the tank to 16 inches, the PAR at the top of the tank is going to drop to 125 PAR. Moving it to 4 inches reveals 1600PAR at the top of the tank, bleaching, burning and killing all coral at that distance.

 

 

Put any distance you like for your light and tank, youll see that it does NOT exceed the radiation of the Sun.

 

Given the Sun does not change its distance to the Earth during a day, its reduction in intensity is governed by other factors, ie turbidity, fog, clouds, etc.

 

One could put a single 3 watt LED 1mm distant from a coral, and exceed 500PAR at that point of the coral, but imagine that the rest of the tank with a PAR of zero.

 

Nutshell:

A coral 36 inches under water under the Sun will get pretty close to full PAR of the sun, minus for refraction and absorption.

A coral 36 inches under a light, with 500 par at the top of the tank, is going to have the same refraction and absorption as the Sun, but far far less PAR at the bottom of the tank due to the Inverse Square Law.

[Hart24601]

Lol. All my tanks have over 500 par on the upper rockwork with mid rock being avg of 300. At full blast my biocube with steves led custom kit is 3000 PAR right under the water and 900 on the rock. Clearly I don't run it that high, but it EASILY exceeds the sun over 12 hours.

 

Here is the PAR chart measured with apogee of my biocube. This was 1 year ago, I tested again recently and it didn't drop, but I have it turned down to 500 PAR on the rock.

[farkwar]

Im not going to do Calculus, just some cookbook math.

 

700 at the top.

380

150

70 at the bottom

1300 total

325 average under LEDs

 

700 at the top

700

700

700 at the bottom

2800

Equals 700 average under the Sun

 

Like I wrote, you can take a single 3 watt NW LED and get maybe 3000+ PAR at 1mm away from the coral, or quantum meter Sensor.

 

In other words, take your tank outside, here almost Fall, on a cloudless day Turn on your lights, full intensity. The Sun will overpower your LEDs all day long. I doubt from about 7 to 7 you could even tell your lights are on.

[Hart24601]

You see my photo right? That is in the water par values at different depths. Those are measured with a apogee par meter. You don't need to measure the bottom and average for a coral on the rock, lol, the acro at the top doesn't care about the bottom - it gets, in its position on the rock, more par than the sun and much more pur. The 3000 isn't the total, that is the reading at the surface. Your right about it dropping off exponentially, but you are way off the starting value. Even my 65g with 2 reefbreeders value fixtures makes 1800 in the water at the top, the highest coral would be exposed to 1200par if I ran them that high. That coral doesn't care what the reading is farther down the tank. Just where it is, and that is far stronger than the sun in par and really in pur.

 

The tank outside wouldn't look bright because our eyes are most sensitive to yellow and green, which tanks don't have much of.

[farkwar]

All i am disputing is the notion that our reef lights are more intense than the Sun, in a typical reef tank.

 

They are not.

 

 

If that was not your point, i misunderstood what you wrote. And then nevermind.

[acrab78]

10 hours

[Hart24601]

All i am disputing is the notion that our reef lights are more intense than the Sun, in a typical reef tank.

 

They are not.

 

 

If that was not your point, i misunderstood what you wrote. And then nevermind.

[Hart24601]

That's pretty much what I am saying using the advanced aquarist article as a reference. I don't mean that I can open the tank and make the world experience the full intensity of the sun. But as the article says, 525 par on a coral for 12 hours exceeds the daily photosynthetic light energy from the sun 2" down in a Hawaiian tide pool in winter.

 

To the coral in my tank getting 1000 par for 14 hours a day, there is no ocean in the world where it would get that amount of light intensity, in PUR, not that I run the tank like that. I have linked sources for that, not much more I can say.

[farkwar]

Have you seen any experiments done with light 24 hour captive reef animals versus 12 hours versus say 6 hours?

 

Have you seen any experiments that show that more light is detrimental?

 

I havnt seen them.

 

Got any links if you have.

[tlombardo]

I don't know nearly as much about any of this but I would assume you all had seen this as it's from 2009. Just in case here it is.

 

Quote from Advanced Aquarist article: here

 

"Recent research has revealed that an excessively long photoperiod and spectral qualities can temporarily disrupt the reproduction cycle of zooxanthellae. Wang et al. (2008) have described effects of both of these factors in a highly detailed examination of zooxanthellae isolated from a 'Torch' coral (Euphyllia glabrescens; See Figure 4)."

 

Source referenced in the article:

1. Wang, L.-H., Y.-H. Liu, Y.-M. Ju, Y.-Y. Hsiao, L.-S. Fang and C.-S. Chen, 2008. Cell cycle propagation is driven by light-dark stimulation in a cultured symbiotic dinoflagellate isolated from corals. Coral Reefs, 27:823-835.

Unfortunately the study doesn't seem to be free to view. If someone feels the urge to buy it let us know what you find!

 

Tony

 

Edit: Here is another quote from the article that goes slightly more in depth about prolonged photo-periods

 

"In an experiment where continuous illumination was provided for 72 hours, zooxanthellae maintained a natural progression of reproductive phases for at least the first 11 hours. At Hour 17, unnatural populations of phases were noted, and the trend lasted for the duration of the experiment. Notably, zooxanthellae contained an abnormal number of chromosomes (designated as '3-4 Chromo' in Figure 10) and failed to divide in an orderly fashion."

 

 

Like 50th edit: The article also addresses the issue of matching natural sunlight in our aquariums in the conclusion fairly concisely, and the answer is yes we can. This was in 2009.

 

Ok last but probably most important edit:

 

I found a study from 2010 that compared growth in multiple samples under 4 different photoperiods (with same intensity) that covered 8 on 16 off, 12 on 12 off, 16 on 8 off, and 24 on 0 off. They also did 8 on 16 off with 2 different, higher levels of intensity. This lasted 18 weeks.

 

Pretty much the whole conclusion copied and pasted:

"No positive correlation between light availability and growth was observed under the given experimental conditions. Neither with increasing photoperiod duration, nor with increasing irradiance, nor with increased daily light flux. This indicates that light was not the limiting factor for coral growth and was most probably in excess."

 

"Corals were able to adapt to prolonged light duration under light saturating conditions by decreasing their hourly rate of photosynthesis. As a result, daily net photosynthesis was not significantly different between corals grown at 8 hours light and 16 hours light."

 

"Factor(s) limiting or inhibiting coral growth in this study could not be conclusively determined. Our results do show that corals are able to adapt to a prolonged light duration under stressful condition and that daily growth rates seem to be correlated to daily photosynthetic rates. Therefore, for coral aquaculture, increasing light availability still seems promising, but remains to be explored under light-limited conditions."

 

Source

[Hart24601]

I don't know nearly as much about any of this but I would assume you all had seen this as it's from 2009. Just in case here it is.

 

Quote from Advanced Aquarist article: here

 

"Recent research has revealed that an excessively long photoperiod and spectral qualities can temporarily disrupt the reproduction cycle of zooxanthellae. Wang et al. (2008) have described effects of both of these factors in a highly detailed examination of zooxanthellae isolated from a 'Torch' coral (Euphyllia glabrescens; See Figure 4)."

 

Source referenced in the article:

1. Wang, L.-H., Y.-H. Liu, Y.-M. Ju, Y.-Y. Hsiao, L.-S. Fang and C.-S. Chen, 2008. Cell cycle propagation is driven by light-dark stimulation in a cultured symbiotic dinoflagellate isolated from corals. Coral Reefs, 27:823-835.

Unfortunately the study doesn't seem to be free to view. If someone feels the urge to buy it let us know what you find!

 

Tony

 

Edit: Here is another quote from the article that goes slightly more in depth about prolonged photo-periods

 

"In an experiment where continuous illumination was provided for 72 hours, zooxanthellae maintained a natural progression of reproductive phases for at least the first 11 hours. At Hour 17, unnatural populations of phases were noted, and the trend lasted for the duration of the experiment. Notably, zooxanthellae contained an abnormal number of chromosomes (designated as '3-4 Chromo' in Figure 10) and failed to divide in an orderly fashion."

 

 

Like 50th edit: The article also addresses the issue of matching natural sunlight in our aquariums in the conclusion fairly concisely, and the answer is yes we can. This was in 2009.

 

Ok last but probably most important edit:

 

I found a study from 2010 that compared growth in multiple samples under 4 different photoperiods (with same intensity) that covered 8 on 16 off, 12 on 12 off, 16 on 8 off, and 24 on 0 off. They also did 8 on 16 off with 2 different, higher levels of intensity. This lasted 18 weeks.

 

Pretty much the whole conclusion copied and pasted:

"No positive correlation between light availability and growth was observed under the given experimental conditions. Neither with increasing photoperiod duration, nor with increasing irradiance, nor with increased daily light flux. This indicates that light was not the limiting factor for coral growth and was most probably in excess."

 

"Corals were able to adapt to prolonged light duration under light saturating conditions by decreasing their hourly rate of photosynthesis. As a result, daily net photosynthesis was not significantly different between corals grown at 8 hours light and 16 hours light."

 

"Factor(s) limiting or inhibiting coral growth in this study could not be conclusively determined. Our results do show that corals are able to adapt to a prolonged light duration under stressful condition and that daily growth rates seem to be correlated to daily photosynthetic rates. Therefore, for coral aquaculture, increasing light availability still seems promising, but remains to be explored under light-limited conditions."

 

Source

Wow, nice job!