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Lighting schedule twice a day?

Abarth_1200

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So I currently run my community tank (60L non co2 some plants) on a timer to have a period of light on in the morning, then dim to 10% until 5pm where I have another 5 hours @90%

I'm about to start co2 alongside a new tank, I know what the answer will be, one lighting period but would like to know why, and if there's any way I can work around having a max 1 hour window of light at 7am (possibly 15%) then off until I want to start my plant lighting period (probably 1pm-9pm with co2 starting for this time or before depending on how it sets up with levels etc)

On that basis would it be possible to have a different plant lighting schedule during Saturday and Sunday? 10-6 possibly.
 
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Wookii

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I run my tanks with around 12-14 hour lighting schedules (including 1/2 hour ramps) without any issue, just with lower overall intensity. Whilst a brand new high tech tank might be better with a reduced photo period initially until the plants start to grow well and the tank becomes established, I don't think there is any reason not to have a longer photo period on an established tank, or have to mess around with multiple daily lighting periods.
 

tiger15

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I run a high tech tank with two lighting periods of 4.5 hour each in the morning and evening. I do it to fit my viewing schedule, not for the sake of plants. I synchronize CO2 and lighting period, and don’t provide CO2 1 hour before light on, and stop CO2 1 hour before light off as many experts recommend. My plants are doing fine and that’s good enough, and don’t believe either way will make a substantive difference
 

Abarth_1200

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For low tech tanks there is an idea from Diana Walstad to use two lighting invervals to allow a gap for CO2 levels to recover via diffusion from atmosphere before the second lit interval; obviously this does not apply to CO2-injected tanks.
See I do this already but because I don't have co2 currently I don't see there being any issues. What I don't want to have is problems doing 2 photoperiod and co2 because I know everything is amplified when adding nutrients
 

Abarth_1200

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I run a high tech tank with two lighting periods of 4.5 hour each in the morning and evening. I do it to fit my viewing schedule, not for the sake of plants. I synchronize CO2 and lighting period, and don’t provide CO2 1 hour before light on, and stop CO2 1 hour before light off as many experts recommend. My plants are doing fine and that’s good enough, and don’t believe either way will make a substantive difference
I wonder if my 1 hour in the morning wil use up any remaining co2 that didn't gas off overnight. But your way sounds like it's working fine
 

_Maq_

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All plants wake up (start photosynthesis) with daylight, and end 10 to 13 hours later, no matter what the artificial light is like. So, you can push photosynthesis period onto late hours only if you keep your tank in a room devoid of any daylight.
It follows that evening CO2 injection is counterproductive.
 

tiger15

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All plants wake up (start photosynthesis) with daylight, and end 10 to 13 hours later, no matter what the artificial light is like. So, you can push photosynthesis period onto late hours only if you keep your tank in a room devoid of any daylight.
It follows that evening CO2 injection is counterproductive.
Are there any data to show that aquatic plants stop growing after 13 hour photo period. One sign of photosynthesis shut down is certain fine leaf stem plants such as ambulia and Cabomba will close up foliage. I provide 16 hour photo period from 7 am to 11 pm with a 7 hour intermission in between, and have never observed foliage close up in stems, only to observe foliage open up in the morning after night rest.

Weed growers provide as much as 18 hour photo period for vegetative growth, but flowering and fruiting stage require half as much photo period to prevent crop failure Aquatic plant growing is all about vegetative growth with no constrain on flowering and fruiting, so longer photo period shouldnt hurt, right?

 

_Maq_

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I provide 16 hour photo period from 7 am to 11 pm with a 7 hour intermission in between, and have never observed foliage close up in stems, only to observe foliage open up in the morning after night rest.
I trust you but it sounds very very surprising to me. The only explanation which comes to mind is CO2 injection. We can speculate that plants regularly exposed to such long lighting period without any decrease in CO2 content may change their habits. Maybe...
Weed growers provide as much as 18 hour photo period for vegetative growth, but flowering and fruiting stage require half as much photo period
In horticulture and agriculture it often depends on the region of origin of a given species. Equatorial plants are usually negatively affected by 'long day', they don't initiate flowering. Quite the contrary holds for most species originating from moderate to cold climatic zones.
 

tiger15

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In horticulture and agriculture it often depends on the region of origin of a given species. Equatorial plants are usually negatively affected by 'long day', they don't initiate flowering. Quite the contrary holds for most species originating from moderate to cold climatic zones.
Photo period has great impact on flowering and fruiting, no doubt about it as nurseries regularly manipulate photo period to force or delay flowering. The unknown is how photo period may impact vegetative growth. There are some tissue cultures that provide nearly 24/7 photo period.
 

Thea B

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For low tech tanks there is an idea from Diana Walstad to use two lighting invervals to allow a gap for CO2 levels to recover via diffusion from atmosphere before the second lit interval; obviously this does not apply to CO2-injected tanks.
This is an interesting idea. I might experiment with this.
 

Abarth_1200

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Are there any data to show that aquatic plants stop growing after 13 hour photo period. One sign of photosynthesis shut down is certain fine leaf stem plants such as ambulia and Cabomba will close up foliage. I provide 16 hour photo period from 7 am to 11 pm with a 7 hour intermission in between, and have never observed foliage close up in stems, only to observe foliage open up in the morning after night rest.

Weed growers provide as much as 18 hour photo period for vegetative growth, but flowering and fruiting stage require half as much photo period to prevent crop failure Aquatic plant growing is all about vegetative growth with no constrain on flowering and fruiting, so longer photo period shouldnt hurt, right?

Do you have co2 diffused? And how's your schedule for it
 

Yugang

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This is an interesting idea. I might experiment with this.
"if it ain't broke, don't fix it".

In the (sub) tropics, there is about 12 hours full day light summer and winter. So that seems the more natural approach.

Whilst a brand new high tech tank might be better with a reduced photo period initially until the plants start to grow well and the tank becomes established, I don't think there is any reason not to have a longer photo period on an established tank, or have to mess around with multiple daily lighting periods.
This is it.
Shortening the light period, or include a siesta, is meant to create a competitive disadvantage for algae compared to plants. When algae are well controlled, the lighting period is much less of an issue.
 

erwin123

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plants don't stop growing in darkness.... when I did a 72 hour blackout, many of my stem plants responded by growing taller fast! :)
 

Yugang

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plants don't stop growing in darkness.... when I did a 72 hour blackout, many of my stem plants responded by growing taller fast! :)
Burning the sugars they built and accumulated with photosynthesis, and exhaling CO2. Longer internodes, as they reach for light.
I am sure you know your stuff :)
 

tiger15

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plants don't stop growing in darkness.... when I did a 72 hour blackout, many of my stem plants responded by growing taller fast! :)
True. Growth and photosynthesis are two separate processes that don’t have to occur concurrently . Photosynthesis makes sugar utilizing CO2, H2O and light. Growth burns sugar energy to make tissue, chlorophyl, hormone, reproductive cells, toxin, etc by utilizing N,P, K and other nutrients. Respiration is a byproduct of growth. Growth and uptake of nutrients for growth can occur at all time, and not just during the photo period.
 
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