Shortening the day?

[Adamw327]

Just wondering if anyone has ever experimented with this

Basically what i was thinking was keeping whatever your normal photo-period was, but lessening the amount of dark time slowly. Basically to the point where in a 48 hour period, the tank experiences 3 days. What effects do you think this would have on coral, would it possibly increase growth rate?

Or on the other side of the spectrum, lengthening the day

 

[Rare Angels]

I did something like this when breeding clownfish, not sure what effect it has on corals.

 

[dlplunkett44]

It may work to an extent, but as will all photosynthetic creatures, they usually do better with a period of darkness. As long as you don't decrease the dark times past this point, it should work.

 

[hypnoj]

You'll find lots of RC threads on 4 hrs on, 4 hrs off. Or 4 hrs on, 8hrs off.

 

[The Curious]

You'll find lots of RC threads on 4 hrs on, 4 hrs off. Or 4 hrs on, 8hrs off.

I run 4 on, 8 off. To put it basically, corals "collect" energy during the light period, and "use" that energy to grow during the dark period. 4 on 8 off creates 2 "days" each 24 hr period.

I had heard about it before, but what pushed me into starting 4 on 8 off was a local reefer/biologist explaining that corals in the ocean get around 4 hrs of "intense" sunlight each day, when the sun is directly over them. I'm going off what I heard more than what i researched, but he told about a scientific article stating that about 4 hrs is as long as corals CAN perform photosynthesis. So by that logic any extra time that the light runs is for our amusement, and of course to grow more of that algae on our glass that we all love so much.

I was worried about my fish when I started it, but they don't seem to mind at all. I love it because when I wake up a 5 A.M, my lights are on and I can make sure everything is OK before I head to work. When I get back from work, lights are either on, or about to come on for the next 4 hr cycle. It fits my schedule perfectly, and the corals love it.

Be careful though...Waking up to a tank with 450 watts of LED brightening up my living room makes me feel like a vampire walking into sunlight.

 

[ReeferBatman]

any good links to experiments?

 

[TimeConsumer]

I spent a few hours searching google scholar and I can't find any studies that tested altered circadian cycles on corals. One that tested it on soybeans, but it was more focused on reproductive stages. I did find quite a few interesting things on light cycles and coral growth though! A 16 hour photoperiod and an 8 hour photoperiod had zero difference on galaxea growth rates given equal light intensity. So if you're running your lights longer than 8 hours a day specifically to achieve more growth, save your electricity.

 

[Tigé21v]

A while back I read somewhere on here a thread on the 4 on/ 8 off cycle, I (think) there was a link to a study that contends corals can only use/store 4 hours' worth of light at a time. More than 4 hours, the light starts to stress/damage the coral, and at the end of the photoperiod, the coral first uses its stored energy (from the first 4 hours) to repair itself instead of putting that energy towards new growth. I think the thread went on to say best results were seen with zoas/palys and sps, the increase in lps growth was not as significant.