24 hour photo period?

[The Pet Factory]

I wonder how the corals would respond to a 24 hour lights on environment? I don't think they would like it but I'm just curious, would they start to open and eat (the corals that feed at night) if the lights just stayed on all the time or would they just start to starve to death?
Any insight would be appreciated.
Chad.

 

[KingBlingTx]

It's my understanding that this would be fairly detrimental. The zooxanthellae can only produce nutrients via photosynthesis for a certain period of time before they become "exhausted". Continued lighting (with no recovery period) offers no additional benefit.

 

[mike_cmu04]

Ya from what I have read i have seen nothing that says this would be positive. You would also probably stress your fish out and have some algae problems

 

[The Pet Factory]

I would imagine would be harmful in a bunch of ways but I was just curious if anyone has read any studies about trying it out. Just curious more than anything.

 

[Randy Holmes-Farley]

I've never seen any careful study that actually tested it.

FWIW, macroalgae seem to do fine in 24/7 lighting (I used it for a decade or more in my refugia), and the simple hand waving arguments for or against would seem to equally apply to macroalgae and corals.

 

[slapshot]

Actually some one has....I can't remember the artical I read. I may have gotten it from McSaxmaster. The bottom line was the zooxanthellae reach a saturation point and need some downtime. The question was how much. As I remember it was not very long, several hours. It was the outcome of the artical that you could speed up the growth by repeated exposure and then downtime for a couple of hours.

You would have to know each zooxanthellae saturation time to maximize this but for sure you could run your lights for 10 on 2 off, 24/7 and improve growth. This study did not measure the stress this might cause though. You could improve our growth by feeding us 24/7 and only sleeping for two hours but I don't think our nervous systems would appreciate it.

 

[cdeboard]

I have also read that corals only add to their calcium base (skeleton) at night.

 

[greenbean36191]

The zooxanthellae can only produce nutrients via photosynthesis for a certain period of time before they become "exhausted".

No. Zoox continue photosynthesizing at the same rate for as long as the light is on. For some reason, this idea that photosynthesis bogs down over time seems to be widespread in the hobby.

Long photoperiods do alter the cell cycle of zoox though, preventing them from dividing. This probably isn't a good thing in the long-run.

I have also read that corals only add to their calcium base (skeleton) at night.

No. They calcify day and night, but calcification is greatest during the day.

 

[baxterdawg]

One thing to keep in mind is that nearly all the living animals we purchase to keep in the aquariums have naturally evolved to live with a light/dark cycle. Because of this, some physiologies in both corals and fish need the dark phase to retain normal biological function. If you have any fish in the tank that is on a 24 h light cycle, they will start to suffer after a few months. Particularly because their immune system and natural circadian rhythms will be compromised.

There is alot of research that demonstrates that reduced sleep in animals increases mortality and morbidity, so the logical assumption is that this is true with corals as well.

 

[Airwolf75]

Once my timer stuck during a vacation and the tank went 3 days with no dark. The results were amazing polyp extension, faster growth rate, and bright colors.

Ok, not really,the tank was really hot, there was a mess of algae and everything looked semi-bleached. I bet a few more days of that would have been ill advised.

 

[muerk1]

I know that terrestrial plants can function fine with 24/7 lighting. I believe that as long as there are no limiting nutrients, i.e. carbon, nitrogen, phosphorus, etc., the citrus cycle (which turns light, water, and carbon into sugars) will go on indefinitely with no ill effects. Macroalgaes are much more simple in physiology than terrestrial plants, so I would think it would be fine. I have tried both light cycles on my fuge with no problems, but animals might react differently. Corals and their zooxanthellae would probably be fine with 24/7, but more research would be needed.

 

[Driftdiver]

Unfortunately, I have had my lights remain on for 4 days straight and witnessed the aftermath. Due to a sudden illness and death of a family member, we were forced to go up North for a few days. I had asked a friend to come by my house and look in on everything, but apparently he forgot. I was aware that one of my timers on my 29 wasnt working, but I did not realize that the ones on my 220 and 40 were also broken. Long story short, the lights remained on full from Thursday morning until Sunday or monday.

Before I left the tank parameters were perfect and everything was growing. When I returned, I had lost 2/3rds of my corals and some of my fish. THese were well established animals. A brain that I had been growing out for 3 years, fish that I had for similar periods, and some corals that were 5+ years old in my system. Part of this was due to the snowballing effect of one coral dying/going toxic causing another to go. Either way, its not good.