How many hours does algae require during respiration?

[Miami Reef]

I’d like to keep the ATS on as long as possible, but how many hours does algae require for respiration for the best growth?

 

[Randy Holmes-Farley Verified Community Expert]

I don’t think the answer is clear. I experimented on my refugium, between 24/7 lighting and 12 h on and 12 h off.

I saw no apparent difference, and went to 12/12 to save electricity.

 

[Naekuh]

I’d like to keep the ATS on as long as possible, but how many hours does algae require for respiration for the best growth?

i think the given standard is 16/8. 16 hours on, and 8 hours off.
The 16 hours on usually on a parabellum with your DT light schedule.
So when the DT is on, the ATS is off, and vice versa.

I do know people do it more to stabilize pH tho then growth.

But it also depends on what algae you are cultivating / scrubbing.

For example, a ATS should be tuned with phosphates messurements, and your light cycle should be adjusted depending on how much phosphates is left in the tank each cycle, if you really want to get controlish about it.

 

[Dan_P]

I’d like to keep the ATS on as long as possible, but how many hours does algae require for respiration for the best growth?

I am under the impression that some algae are OK with 24 hours of light, and some need a lights out period for good health. I assume your ATS will be a mixed culture and you may need to experiment. I would expect to see a shift in what grows and how much grows as the light period increases. I think there is a chance that cyanobacteria will dominate the culture if too much light stresses some of the algae inhabitants.

 

[Miami Reef]

I don’t think the answer is clear. I experimented on my refugium, between 24/7 lighting and 12 h on and 12 h off.

I saw no apparent difference, and went to 12/12 to save electricity.

Thank you. 12/12 sounds good to me.

 

[taricha]

check this out - Caltech study on caulerpa.
https://www.caltech.edu/about/news/...e-cell-is-intertwined-with-daily-self-rhythms
Here's their video of what caulerpa does with its chloroplasts over a day/night cycle. The chloroplasts can move a lot because caulerpa are large single-cells.

It can grow just fine on 24/7 lighting, but it was much better on 12/12.
this image from the bottom of the linked article is the comparison between the 24 on and 12/12. Same total light intensity over a day.

 

[Miami Reef]

check this out - Caltech study on caulerpa.
https://www.caltech.edu/about/news/...e-cell-is-intertwined-with-daily-self-rhythms
Here's their video of what caulerpa does with its chloroplasts over a day/night cycle. The chloroplasts can move a lot because caulerpa are large single-cells.

It can grow just fine on 24/7 lighting, but it was much better on 12/12.
this image from the bottom of the linked article is the comparison between the 24 on and 12/12. Same total light intensity over a day.

Very cool. I had a feeling less was more.

 

[taricha]

Very cool. I had a feeling less was more.

To be clear, this doesn't actually answer your question as to whether 12/12 or 16/8 or some other schedule is optimal.

But I thought it was interesting that even for algae that can grow just fine with 24hr on, what they do with a light/dark period is totally different, and it helps them significantly.

 

[Doctorgori]

I know photo period studies have been done with terrestrial plants, specifically cannabis and I thought not much growth difference was gained past 18hrs
Regardless it was less proportional than you would imagine… not sure how much that translates to algae, but it could be similar