# Turning lights off for a few hours middle of day?



## natebuchholz (Sep 28, 2013)

There is little to no issue with this. The only issue is killing the growth momentum at its peak. You can always test it and see if there are adverse effects but, there is little proof that it is good or bad. 

I know I didn't answer your question; there are many people that swear by this method and others that are very opposed. If you can't enjoy your tank then I feel its a good idea to change your light cycle so you can, even if the above solution is not the final one.


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## Kubla (Jan 5, 2014)

Some folks think a broken light cycle is much more detrimental to algae than to other plants.


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## jeffkrol (Jun 5, 2013)

KGNickl said:


> So I want to run my aquarium lights when we are around to view but not go beyond 10 hours a day due to algae problems. When I run 12 hours I have them on 30 minutes less in the morning and turn them off 30 earlier than I would like in the evening. Since I dropped down to 10 hours of light the algae problem has been much more reasonable.
> 
> So I'm wondering about having a 3 hour break in middle of the day? Is there any major reason for not doing this? I could image if the tank was in a dark room or basement it might not be a good idea. The aquarium is in our main area of our house so its not like its dark during the day (not direct sunlight but enough windows and openness to keep the room comfortable. It would almost be like a cloudy day every day around the same time during this 3 hour window....? So curious what everyone's thoughts are about this? Tank has plants and fish (betta, guppies, and neon tetras). Also the tank is a 29 gallon tank w/ CO2 injection and a 30" Finnex Planted+ light.
> 
> ...


a bit of science:
ftp://saleskalab.eebweb.arizona.edu...PIRE Field Course/Chazdon and Pearcy 1986.pdf

Stomatal responses are of course not very relevant to aquatic plants.
Bottom line: It takes time to "start the engine" and stop it.. 
As to algae it "could" be they can't "idle" as well as higher plants..


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## natebuchholz (Sep 28, 2013)

jeffkrol said:


> a bit of science:
> ftp://saleskalab.eebweb.arizona.edu...PIRE Field Course/Chazdon and Pearcy 1986.pdf
> 
> Stomatal responses are of course not very relevant to aquatic plants.
> Bottom line: It takes time to "start the engine" and stop it..


Jeff, I am glad for you and your wonderful peer reviewed scholarly sources.


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## chicken (Aug 22, 2007)

A number of people do just what you are considering, whether it's to discourage algae, or simply to have the tank illuminated when they are able to enjoy it. 

All my tank lights are on timers, coming on at various times. Basement tanks come on mid morning, and stay on for 10 hours. One of my dining room tanks is lighted for a couple hours in the morning, then again in the afternoon through the evening. Several other tanks come on at noon, and go off at 8pm. 

I've experimented with a split photoperiod, and haven't noticed any difference in algae or plant growth. It just seems to be a matter of how many hours the lights are on total. Other people have seen different results.


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## nayr (Jan 18, 2014)

photoperiods are determined by time in darkness, not time in light.. If your room in the middle of the day is not dark when the lights go out then your plants just continue the photoperiod, with less input than before.. like a cloudy day.

For most people's aquariums its totally acceptable, you might get more stretching if the plants need more light but its manageable and probably the only thing you'll notice. 

Now if you did end up breaking your photoperiod into multiple's a day it can have several effects from the stress, flowering plants probably wont flower anymore, leaf mutations could develop, growth will be stunted, etc.. Many plants use photoperiods to detect the changing seasons, if you signal winter is coming many non-tropical plants will go into emergency mode trying to prepare by consuming stored nutrients rapidly to encourage root growth or reproduction.

Turning the lights off in the middle of the day does much less damage than turning the lights on in the middle of the night.


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## Jeff B (Oct 16, 2010)

KGNickl said:


> So I want to run my aquarium lights when we are around to view but not go beyond 10 hours a day due to algae problems. When I run 12 hours I have them on 30 minutes less in the morning and turn them off 30 earlier than I would like in the evening. Since I dropped down to 10 hours of light the algae problem has been much more reasonable.
> 
> So I'm wondering about having a 3 hour break in middle of the day? Is there any major reason for not doing this? I could image if the tank was in a dark room or basement it might not be a good idea. The aquarium is in our main area of our house so its not like its dark during the day (not direct sunlight but enough windows and openness to keep the room comfortable. It would almost be like a cloudy day every day around the same time during this 3 hour window....? So curious what everyone's thoughts are about this? Tank has plants and fish (betta, guppies, and neon tetras). Also the tank is a 29 gallon tank w/ CO2 injection and a 30" Finnex Planted+ light.
> 
> ...


I do 1 light 7:00 am to 2:00 (7 hrs), it goes off
2nd light comes on 4:45 to 10:15)~(6 hrs)

Lights are 10 inches above tank, so low light, low tech.

I'm experimenting with having both lights on for two hours during the morning and 2 hours during the evening when I am around because it looks better and I'm trying to get more colour in the plants. Also experimenting with PPS dosing but only every other day. Dropped PPS dose to 2.5 mls of Macros and 2.5 mls f Micros because I don't have a lot o fast growing plants to suck them up. Plant reds are a bit better now.


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## fishbone11 (Sep 11, 2014)

I use a 3 hr mid day break. I had read (possibly in Walstad's book) that all co2 is consumed in 3 to 4 hrs, and that by turning lights off, co2 is regenerated to be consumed in the second light period.
I have very good growth and minimal algea problem. Then again, I have not used another light schedule to compare.


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## HDBenson (Jan 26, 2015)

In the most recent edition of "Ecology.." Walstad suggests a photo period of five hours on, four hours off, and another five hours on.her reasoning is, as mentioned, in a non-injected system that plants use up the available CO2 that is generated during dark periods. The twelve hours off produces enough CO2 to "last" for approximately five hours. The four hour respite supposedly brings the Co2 levels(even in a dark, no artificial light, but not total darkness either room) back to "pre-dawn levels" as she refers to it. So yeah, try it if you want.


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