Refugium Lighting - 24/7 is Bad-Says Kent Marine University

[Minh Nguyen]

It has being a long while since I study basic Biology (25+ years ago). My classification is not up to date. My point is that asexual reproduction when time is good and sexual reproduction when time is bad has being very well documented in various organism from simple to complex. Even bacterial reproduce asexually until condition become unfavorable then form spores (Clostridium sp.). Some insect does it (aphids), plants. There is no reason that Caulerpa should not do it. In fact, I would argue that it is well documented that Caulerpa sexually reproduce with stress. Turn your light off for a day or two and your Caulerpa will go sexual every time (if it is large enough)
IMHO and IME, Caulerpa reproduces by growth and fragmentation when there is plenty of room, water moment and light. As they become overcrowded, current decreases, light decreases and nutrients decreases. If this is enough, they will go sexual to find better condition.

 

[MediaOne]

I find this post quite interesting. It goes contrary to the majority of current refugium (more specifically, caulerpa) knowledge. I have been running 24/7 and never had a sexual event occur. I agree with the statement earlier about Caulerpa reproducing when it believes itself to be threatened (from lack of light, nutrients etc), that is a basic biological principle.

What about Mr4000.com he runs his entire tank off the 24/7 principle.

Now would be an appropriate time to mention the Ecosystem. It has a 24/7 lighting recommendation as well. They certainly do not have tons of customers complaining about algae going sexual, they wouldn't be around and doing so well.

I believe in 24/7

Just my 0.02

Cheers!

 

[ColdinCanada]

I have been running an ecosystem set up with a 24/7 light period for 15 months now. My caulerpa has never gone sexual. I thought one of the reasons we light 24/7 was to allow the algae in the refugium to outcompete the algae that may try to grow in the main tank. It seems to me if you go to 12/12 you've shifted the balance back to the main tank and more algae will grow there where the lighting is more intense.

Just my opinion.
Jay

 

[SPC]

Posted by Coldin Canada:
I have been running an ecosystem set up with a 24/7 light period for 15 months now. My caulerpa has never gone sexual.

- I thought that turf algae was used in the ecosystem.?
Steve

 

[ColdinCanada]

SPC,

Nope, Leng recommends caulerpa. www.ecosystemaquarium.com.

Jay

 

[SPC]

Yes you are correct Jay, I was thinking of the turf scrubber
Steve

 

[Reef55]

I am running a 55 gallon reef (10 different SPS a couple LPS and a bunch of softies). The only filtration is an eco-system type refugium under the tank which has the eco-mud and a couple different types of algaes (red turf to spaghetti to caulerpa). I have been running a LOA 65watter 24/7 for a little over a year now. None of the algae has ever gone sexual, and it is almost always too crowded since I forget to prune. I have more than enough critters in my tank / fuge (there is a VERY fat female mandarin that I've had for about 18 months to attest to this). I can honestly not see any reason why I should switch to 12/12. Just about every post that mentions their algae going sexual is from someone running 12/12.

 

[Anonymous]

I have had caulerpa in my tank,12 refuge,and 24 hours. 24 hours has never gone sexual. But the other two have. I'll stick to 24 hours.

 

[Minh Nguyen]

Back to the original poster. I keep my refugium on a 12 hours light /12 hours darkness cycle. However I think the Kent article is full of baloney. It is obvious that Caulerpa does not go into sexual reproduction just because of the 24/24 light cycles.

 

[Ike]

Posted by Dwight:
Don't we have any experts out there that can settle this debate?

-The experiment that Dr Reef posted about seems to be in the "expert" category to me, am I missing something?? :?
Steve

Well Louey it looks like we had a good turn out of "experts". I am going to keep my lighting at 24/7 and prune regularly. And in reply to SPC, yes you are missing something. :lol:

 

[Basil63]

Also, last time I checked, my oak tree in the front yard didn't receive 24 hours of light, and if it did, I don't think it would be better off for it.

I don't know too many people with Oak trees in their refugiums, do you?
Basil63

 

[Anonymous]

Originally posted by DanConner:

I never had too much trouble with algae going sexual; but I did gain the impression that 24/7 gave an advantage to hair algae over caulerpa.

hmm. My refugium has a fair amount of hair algea in it. I run 24/7.

Does anyone else agree with DanConner that 24/7 help hair algea out compete caulerpa?

 

[Anonymous]

It does in our University tanks. But who cares right? Both algaes are doing nutrient removal.

I'm going to keep my home tank on 12/12 though. Pruning keeps them from going sexual, and 12/12 helps the algae reach it's max growing speed.

 

[Anonymous]

Originally posted by Dr. Reef:

It does in our University tanks. But who cares right? Both algaes are doing nutrient removal.

You are probably right, but I would be very happy to never see hair algea anywhere in my system. It brings back to many bad memories! 8)

I have not changed from 24/7 yet, but I am still leaning towards 12/12 or reverse daylight (almost the same).

This thread clearly shows that there are more than one way to run a reef succesfully. With 62 votes, 29 votes are for 24/7, and 33 against it. That is only a difference of 4 votes total. I was hoping for a more definative vote, but it is what it is. Both sides have merit. I guess it proves that none of us are necessarily doing it wrong!

 

[Anonymous]

This post is for reference more than anything. Last night I decided to go ahead and change my refugium lights to 12/12. I have a fair amount of red slime algea in the refugium at this time. The critters have been multiplying prolifically. The caulerpa has never really taken off. The caulerpa brachypus has been almost choked out by the red slime. The Red "bubble" looking algea has grown fairly well.

We'll see what effect 12/12 will have.

 

[kysard1]

The biggest cash crop plant in the world is often grown indoors under halides for 24/7. Then to induce flowering (going sexual) the lights are switched to 12 on/12 off. The hormone which induces flowering is light sensitive meaning with 24/7 it never builds up. I image Macro Algae is similiar.

 

[Anonymous]

regardless of the sexual reproduction issue-all plants need to respire-there is almost always a point at which more light will not be more beneficial than a day/night cycle.

i'm willing to bet that the macros will actually do a better job of completely utilizing the various materials they feed on/absorb more efficiently/completely with a night cycle. :wink:

 

[Anonymous]

The biggest cash crop plant in the world is often grown indoors under halides for 24/7. Then to induce flowering (going sexual) the lights are switched to 12 on/12 off. The hormone which induces flowering is light sensitive meaning with 24/7 it never builds up. I image Macro Algae is similiar.

the experts on that subject say differently-for growth,over 18hrs. probably does NOT contribute to growth/sugar metabolization-(i can pm you with some excellent links, by the way :wink: )

the hormone issue is a seperate one-and also interacts with the growth issue-affecting vegetative growth negatively,btw :wink:

 

[Anonymous]

one more-for all of you that also have hair algae-i'll wager(where's yancey? :wink: )that with less than 24/7 you will find that your macro's don't slow down, but your hair algae does- i've noticed this occur both in fresh and saltwater tanks-hair algae allways went away when going from 12+ hrs light/day to 8 hrs., with no adverse effects on the higher plants.

in non scientist terms-i think it's like a matter of the light 'energy' being made available-excess energy going into the system will end up getting utilized by another 'oppurtunist'-the algaes(and higher plants)are really oppurtunists of light,in a manner of speaking-get rid of the excess, and the variety/amount of oppurtunists will also go down!

also fwiw-it may be a good idea to make the change gradually-i think that any major, quick change of environmental parameter can cause caulerpa's to go sexual-as a self defense mechanism in reaction to the change,but i think it's not the actual photoperiod that's the 'bottom line' mechanism for the switch.just mho.

 

[Minh Nguyen]

The biggest cash crop plant in the world is often grown indoors under halides for 24/7. Then to induce flowering (going sexual) the lights are switched to 12 on/12 off. The hormone which induces flowering is light sensitive meaning with 24/7 it never builds up. I image Macro Algae is similiar.

Different plants or animal have different signal for reproduction. Just because one plan have one signal does not mean another plant, or algae would have the same signal.
IME, Caulerpa species goes sexual when crowned, or shock in some way like water change. I know for sure that if the Caulerpa is large enough, a water change will trigger Sexual reproduction. I assume that it is the temperature or salinity change, but maybe because of other factors. I have done experiments with my sump, if the Caulerpa is crowded, and if I shut the light off for one cycle >24 hr of darkness, the Caulerpa will go sexual.
From the above observation, IMO, Caulerpa goes sexual when stressed.

Minh