Does phyto culture need darkness?

[Formulator]

I just set up a phyto culture and its near a window, but also next to my refugium which is on a reverse lighting schedule from my DT. So the phyto culture will never get complete darkness. It will get direct light from the fuge for 16 hours and indirect light from the window the rest of the time. Is this a problem?

 

[ISpeakForTheSeas]

I just set up a phyto culture and its near a window, but also next to my refugium which is on a reverse lighting schedule from my DT. So the phyto culture will never get complete darkness. It will get direct light from the fuge for 16 hours and indirect light from the window the rest of the time. Is this a problem?

It should be fine:

People have run 24/7 light before, but whether or not that's ideal or leads to faster phyto growth depends on a ton of different factors: species, light spectrum, light intensity, temperature, nutrient levels, etc. (these listed ones are probably the most important, but others like pH, flow, and more will also play a role).

All of these factors influence growth rate, cell size, nutrition, sometimes color, etc. of a phytoplankton culture.


As an example to showcase this, low to moderate light intensity over a 24:0 (light:dark) photoperiod is likely going to show relatively higher growth than low to moderate light intensity over a 16:8 photoperiod, but high light intensity over a 24:0 photoperiod may actually result in slower growth than high light intensity over a 16:8 photoperiod.


These variables are why some people report higher yields/faster growth at one photoperiod and lower yields/slower growth at another, and why some people sometimes have conflicting reports on which photoperiod is better for a specific phytoplankton culture.

As a general rule, anywhere between 16:8 and 24:0 photoperiods are going to be the best, with 16:8 being the safer but possibly less productive option, dependent on the other factors. There are some exceptions to this rule, but they're the exceptions, not the norm.

 

[Australian_Reef]

No. It’ll be fine

 

[GARRIGA]

Often why one gets green water because lights left on 24/7 or for extended periods. My FW experiments ran couple to several years and I saw no ill affects other than predation or lack of nutrients causing crashes. Darkness wasn't part of the process.

 

[Australian_Reef]

I had a 30l photo reactor running 24/7 to sell on the phyto for years and I always ran 24/7. The amount of spill over light you’ll get will be no prob if you have aeration and food enough for it. But it will speed up growth and saturation

 

[Formulator]

Great! Thanks folks. I once grew a plant in college that needed true dark periods to grow the flowers I wanted, so just wanted to make sure

 

[CannaJake]

Great! Thanks folks. I once grew a plant in college that needed true dark periods to grow the flowers I wanted, so just wanted to make sure

I think I may have grown a hundred thousand of those plants or more in Washington. I would think a photoperiod would be beneficial for circadian rhythm but phyto is new to me so Im learning from you!