# One photo period or 2 or 3??



## takadi (Dec 13, 2010)

Hopefully someone can explain this. I currently have two photoperiods but I have yet to find an explanation of why that break in the lighting schedule helps with algae. Is it the simple act of having a break in the photoperiod that helps with the algae or is it the length of time in which the tank is dark? If it's the former, you can assume that more breaks in the photoperiod would be better


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## yellowsno (May 15, 2011)

im thinking that the breaks give it shorter photo periods for algae i think... but as long as the plants get the full 6 in the day for photo synthesis it will prevent over exposure to light... then again... im not sure and thats im curious about the people who split up their lights on schedule...


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## vincenz (Jan 29, 2012)

By breaking your photoperiod into two shorter ones instead of one long one, what you are doing is giving your tank the chance to replenish CO2. If you have one continuous period, plant photosynthesis uses up most of the available CO2 by the early afternoon and algae gains the upper hand (because comparably, algae is better at CO2 consumption). If the tank has a few hours rest, it can kind of overcome this. 

Diana Walstad goes over this in a section of her book calling it the siesta period and it makes sense. I'm not sure how it goes for high light and CO2 injected tanks though. I'm just taking about low tech tanks, but I'm guessing the science is still applicable.


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## yellowsno (May 15, 2011)

hummm during the seista between the 2 periods... is the co2 still on... or is the co2 caonstantly pumping or is it only on when the lights are on?


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## Steve001 (Feb 26, 2011)

yellowsno said:


> hummm during the seista between the 2 periods... is the co2 still on... or is the co2 caonstantly pumping or is it only on when the lights are on?


Taking some lessons from nature in natural bodies of water
1. Co2 production isn't turned off.
2. During partly cloudy days with fluctuating light levels or during rain storms or overcast days co2 is constantly provided
3. During these lower light levels photosynthesis still happens.

The reason people turn off co2 is to save co2.
In a tank with a siesta it's not a complete blackout. It is a period of reduced lighting. Photosynthesis still happens at slower rates.

I've never heard of any benefit to be had for creating a lighting regimen like you describe on, off, on off over a 24 hour period. Stick with your idea of reducing light intensity. See how that works first. then if you have too incorporate siestas, but not over a 24 hour time frame, just during a normal 8-12 time frame.


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## yellowsno (May 15, 2011)

Steve001 said:


> Taking some lessons from nature in natural bodies of water
> 1. Co2 production isn't turned off.
> 2. During partly cloudy days with fluctuating light levels or during rain storms or overcast days co2 is constantly provided
> 3. During these lower light levels photosynthesis still happens.
> ...


hummm so maybe doing 3 3 hour periods with non stop co2 will be better for me then 9 hours straight...


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## sayurasem (Jun 17, 2011)

Hmmm going to switch my photoperiod after reading this thread.
It's going to be 12hrs total light. 6 hours on (6am-11.59am), 4 hours off (12pm-3.59pm), 6 hours on (4pm-9.59pm), finally 8 hours off (10pm-5.59am).

It's because I get up early morning 5.30 to get ready for school, and most of the time come home late 9 at night.


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## vincenz (Jan 29, 2012)

yellowsno said:


> hummm so maybe doing 3 3 hour periods with non stop co2 will be better for me then 9 hours straight...


As long as your tank is near a window where it can receive some sort of natural light, I think you can do something like a 5-hour period, then 3-4 hours rest (like clouds overhead during midday), then another 4-hour period, followed by darkness. Try it out and see how it affects algae.

I have my tank set up next to a window and have light running from 7AM-12PM, then a siesta for 4 hours, then another period from 4PM-9PM, then lights off until the next morning. 

If your tank doesn't get natural sunlight, I'm not sure what benefits, if any, multi photoperiods will have.


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## somewhatshocked (Aug 8, 2011)

That's just one reason.

Many people turn CO2 off after the photoperiod to prevent gassing livestock. 



Steve001 said:


> The reason people turn off co2 is to save co2.


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## antbug (May 28, 2010)

somewhatshocked said:


> That's just one reason.
> 
> Many people turn CO2 off after the photoperiod to prevent gassing livestock.


Yes this is true, but only because most max out the amount of co2 they put in a tank.


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## yellowsno (May 15, 2011)

antbug said:


> Yes this is true, but only because most max out the amount of co2 they put in a tank.


hummm im curious about this... since the co2 is pumped while the light is off would i need more hours of light to keep the fish from sufficating... or would i need to lower the co2 where its no longer keeping my drop checker lime green?


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## Steve001 (Feb 26, 2011)

somewhatshocked said:


> That's just one reason.
> 
> Many people turn CO2 off after the photoperiod to prevent gassing livestock.


How would that occur. Is there any evidence that actually happens ? Or is an example of modern aquarist meme ?

Consider this:
Carbon dioxide supersaturation in Florida lakes
http://lakewatch.ifas.ufl.edu/LWTEAMFOLDER/BACHMANN/CO2_FL_lakes.pdf


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## takadi (Dec 13, 2010)

Steve001 said:


> How would that occur. Is there any evidence that actually happens ? Or is an example of modern aquarist meme ?
> 
> Consider this:
> Carbon dioxide supersaturation in Florida lakes



What is that supposed to prove? Most fish that people keep here aren't from these lakes. Fish being gassed happens all the time, it is just common knowledge.


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## somewhatshocked (Aug 8, 2011)

It happens all the time. Even in tanks that aren't over-saturated with CO2. Dozens - if not hundreds - of posts on the forum about that very thing. Hardly a meme or myth.

Depending upon the tank, plant load, lighting, etc? CO2 can build up when plants aren't using it during lights out. 

I don't max CO2 out on any tank I run. In the beginning of my CO2 days, I routinely gassed livestock with anything other than DIY yeast CO2 at night. Then I realized aeration via surface agitation or some such was necessary (this was a looong time ago). 

Today, even in some of my tanks with what I consider decent flow and surface agitation, I still have livestock that will head to the water surface if the low/moderate CO2 doesn't shut off at night.


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## Jeff5614 (Dec 29, 2005)

Here's an interesting and sort of related thread over on APC.

http://www.aquaticplantcentral.com/...3696-staged-vs-continuous-light-schedule.html


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## Steve001 (Feb 26, 2011)

takadi said:


> What is that supposed to prove? Most fish that people keep here aren't from these lakes. Fish being gassed happens all the time, it is just common knowledge.


It indicates that gassed fish might have other reasons for being gassed. Perhaps it's do to overstocking or too little plant mass.


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## Robert H (Apr 3, 2003)

> Here's an interesting and sort of related thread over on APC.


Niko doesn't post here, but if he wants to argue his case he should post here. I do not see anything in his link that supports the idea that staggered light schedules have any positive affect on aquatic plants. And Have have yet to read how this has any long term benefit for controlling algae. Algae will eventually adapt to the light just as the plants do.

A normal light cycle for the plants depends on what part of the world they come from. I do not know of any natural light cycle that has a "siesta". If you use light to limit algae growth, you are going to limit plant growth at the same time.

I want my plants to have a normal light cycle and get the most out of added C02 as possible with as little fluctuation in C02 and pH as possible. For those people who like to do this and thinks it works for them, more power to you, but I personally would never recommend this to anyone.



> By breaking your photoperiod into two shorter ones instead of one long one, what you are doing is giving your tank the chance to replenish CO2.


That makes absolutely no sense to me. Plants need a certian number of hours to complete photosynthesis, this is why you usually see pearling toward the end of the light cycle and why you get better growth with an uninterupted light cycle.


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## Steve001 (Feb 26, 2011)

somewhatshocked said:


> It happens all the time. Even in tanks that aren't over-saturated with CO2. Dozens - if not hundreds - of posts on the forum about that very thing. Hardly a meme or myth.
> 
> Depending upon the tank, plant load, lighting, etc? CO2 can build up when plants aren't using it during lights out.
> 
> ...


How does co2 build up ?
Using my own experience I've never seen my fish heading towards the surface. 

I run co2 day/night. There's no surface agitation. I have high plant mass and few fish, no more than 20 Heterandria formosa I'd guess, stocked in a 47 gal tank. Water is moved by 2 powerhead pumps. Plants produce O2 which collects into bubbles on the underside of leaves and linger there all through the night and are still there the next day. 

Since I'm pumping Co2 constantly why is my never stressed a fish by too much co2 experience different than yours ?

P.S. Almost forgot. There's no additional filtration other than what goes on naturally in the tank.


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## Jeff5614 (Dec 29, 2005)

Robert H said:


> Niko doesn't post here, but if he wants to argue his case he should post here. I do not see anything in his link that supports the idea that staggered light schedules have any positive affect on aquatic plants. And Have have yet to read how this has any long term benefit for controlling algae. Algae will eventually adapt to the light just as the plants do.
> 
> A normal light cycle for the plants depends on what part of the world they come from. I do not know of any natural light cycle that has a "siesta". If you use light to limit algae growth, you are going to limit plant growth at the same time.
> 
> I want my plants to have a normal light cycle and get the most out of added C02 as possible with as little fluctuation in C02 and pH as possible. For those people who like to do this and thinks it works for them, more power to you, but I personally would never recommend this to anyone.


Well, Robert, I don't know that Niko is interested in arguing his case here since this wasn't posted on TPT. I just ran across it, thought it was interesting and seemed to relate to this thread so I linked it. As to the validity of the info, I can't attest, but quite a few people use a lighting schedule that includes a noon burst. I think that's what is being proposed in the thread, at least that was my take on it.


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## Steve001 (Feb 26, 2011)

Robert H said:


> Niko doesn't post here, but if he wants to argue his case he should post here. I do not see anything in his link that supports the idea that staggered light schedules have any positive affect on aquatic plants. And Have have yet to read how this has any long term benefit for controlling algae. Algae will eventually adapt to the light just as the plants do.
> 
> A normal light cycle for the plants depends on what part of the world they come from. I do not know of any natural light cycle that has a "siesta". If you use light to limit algae growth, you are going to limit plant growth at the same time.
> 
> I want my plants to have a normal light cycle and get the most out of added C02 as possible with as little fluctuation in C02 and pH as possible. For those people who like to do this and thinks it works for them, more power to you, but I personally would never recommend this to anyone.


A natural siesta ( reduced photosynthesis) would occur during partly cloudy days. Days that become overcast for a time or afternoon storms.


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## somewhatshocked (Aug 8, 2011)

Doesn't _indicate_ that at all.

I'm not a fan of arguing here on the forum, as it's a cordial place, but you really ought to read a bit more here on the forum itself before making blanket statements that have, to be quite blunt, been disproved for years.

Not all tanks, plant loads, stocking amounts, CO2 saturations, water parameters, lighting and such are the same. Not by any stretch of the imagination. But it is incredibly easy to gas a tank if you aren't considering periods of photosynthesis and off-gassing via surface agitation or other means (if you don't turn most pressurized CO2 systems off at night).



Steve001 said:


> It indicates that gassed fish might have other reasons for being gassed. Perhaps it's do to overstocking or too little plant mass.


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## antbug (May 28, 2010)

yellowsno said:


> hummm im curious about this... since the co2 is pumped while the light is off would i need more hours of light to keep the fish from sufficating... or would i need to lower the co2 where its no longer keeping my drop checker lime green?


If your co2 is on 24/7, you would need to lower the amount of co2 injected. It's really hard to say how much, but I would guess at least half.


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## Jeff5614 (Dec 29, 2005)

antbug said:


> If your co2 is on 24/7, you would need to lower the amount of co2 injected. It's really hard to say how much, but I would guess at least half.


Yep, just to be safe you'd definitely want to lower it and then gradually begin to add it back.


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## vincenz (Jan 29, 2012)

Robert H said:


> Niko doesn't post here, but if he wants to argue his case he should post here. I do not see anything in his link that supports the idea that staggered light schedules have any positive affect on aquatic plants. And Have have yet to read how this has any long term benefit for controlling algae. Algae will eventually adapt to the light just as the plants do.
> 
> A normal light cycle for the plants depends on what part of the world they come from. I do not know of any natural light cycle that has a "siesta". If you use light to limit algae growth, you are going to limit plant growth at the same time.
> 
> ...


Except if you had read my post, you'd know I was talking about low-tech, no CO2 tanks, not your run-of-the-mill high tech. During the "off" period, the tank is still under natural light, just like clouds on an otherwise sunny day. Is it nighttime when it's cloudy out during the day? No. So is photosynthesis still going on during the siesta? I'd be willing to bet.

Your talk of pearling and added CO2 and pH fluctuations isn't relevant for what I was talking about. Context, please.


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## Wwh2694 (Dec 14, 2010)

One photo period. Too much strain on the ballast on my MH when going on & off. ADA using 10hrs on.


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## sunyang730 (Jan 30, 2012)

The short periods also help control algae I think. I change from a light on every 3 hours for 3 hours to 1 long 8 hours and algae outbreak. So now I have the light back on short schedule and hope that will kill the BBA


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## Brian10962001 (Dec 6, 2011)

I didn't like it, I ended up dropping my lights and going for a much longer photo period. The problem I had was that any plant that would fruit or flower, would grow really rapidly but not large, then would fruit like crazy. The longer photo period and less light seems to be keeping things dedicated to growing instead of fruiting. It probably won't be an issue depending on what plants you have, but everything I keep seems to like the longer photo period.


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## prototyp3 (Dec 5, 2007)

Is this the same niko who went on and on saying he discovered laminar flow? :hihi:


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