photoperiod experiment

[jbdreefs]

So a recent thread I read started my mind to wonder about the photo period we provide for our reef tanks (I wish I book marked the link!). Then, I talked to Dylan which sparked further interest for this topic. How long should the photo period be? Would two photoperiods per day speed up the coral growth?

http://www.advancedaquarist.com/2009/5/aafeature">http://www.advancedaquarist.com/2009/5/aafeature</a>

The article above was interesting because it provides a way for us to compare how our reef lighting compares to the sun (requires a PAR reading). This article leads me to believe that my photo period is too short (9 hours, 6 with daylight source, based on my PAR readings at the middle of the tank).

I think most of us have one photo period per day which sort of mirrors everyday life. What if we did two photoperiods per day?

Benefits that i can think of right off the top of my head:
-more stable PH? My Ph continually climbs and falls as the lights go on and off. Would my Ph vary less, and therefore be better for the tank inhibitants?
-more stable temps (when it's a concern...not really applicable for LEDs). The same concept applies here. Temps correlate to the amount of time the lights are on and off.

The experiment:
Setup two small frag tanks on the same system with the same equipment and vary the photoperiods. One tank will have a typical one photo period per day and the other will have 2 photo periods per day. Both tanks will receive the same amount of light each day (one will just be divided). Stock both tanks with multiple frags.

How to measure the results?
I think the best way to measure the results would be to take two frags of comparable size and measure the change in weight over a period of time. The size of corals can be construed because the two frags may develop different structures (ie. One may branch twice and the other three times.)

What are your thoughts? Does anyone besides Dylan run two photoperiods? Any suggestions on how to modify my experiment?

 

[rdnelson]

Kind of above my pay grade but.....One thing I noticed is that while tying them to the same system will ensure that other parameters are exact, it will also have the affect of leveling out the PH which may not occur on a stand alone system running multiple lighting cycles as opposed to one. I don't know that it would totally wash out your findings but my affect the results some what. Other than that, sounds like a cool experiment. Wish I had the room and resources to do stuff like that.

One of these days I want to come see you set up.

 

[jbdreefs]

Yeah, I agree with what you said. Tying them to the same system will lose the benefits of stability I discussed above. However, I'm most interested in the effect of the photo period. I've read and heard that zooxanthellae only benefit from a certain amount of light. The way it was explained to me is that they are like batteries. You can only charge them for so long before the charging mechanism loses its effect.

I'm hoping to find that two photoperiods will provide accelorated growth. It would be nice to view the tank in the morning before going to work and when i come home with the lights on.

 

[rdnelson]

JBDreefs;755551 wrote:
I'm hoping to find that two photoperiods will provide accelorated growth. It would be nice to view the tank in the morning before going to work and when i come home with the lights on.

I totally agree. I have mine set up so that my wife can enjoy the tank in the afternoons but I can enjoy it at night. The draw back is that it makes it tough to do early morning tank maintenance on weekends. I am an early riser and that is when I am most motivated to get things done. Waiting until early afternoon to start just irritates me. LOL

 

[ripped tide]

I look forward to the end results!! I don't have a controlled tank to compare mind with, so this will help me decided if I should keep this lighting schedule or not

 

[falos]

As far as I know you can do 4 photo periods per day on sps only tanks I ran 2 6 hr photo periods on a mixed reef for a year lps showed increased growth in acans and lobo sum sps grew quickly sum did not grow at all but still retained its colors wen I tried to run 3 periods per day sps took off and lps slowed down and were releasing there zooxanthellae they were not bleaching just releasing there extra
As far as ph went I ran a fudge 24 hrs a day and dosed brightwell reefbuilder in the Ato you will have to find a way to make your ph stable
I started out by gitting my coral use to a 14hr day photo period over a month or so then split it in half giving 6 hrs dark to 6 light
You will have mortality issues sum corals will not take it at all my dunken was one also you may lose your base color on sps like red planets
And of corse you will have alge issues after all your running 2-4 days per day
If using mh or t-5 your bulb life will be cut in half 2 cycles 6 months 3cycles 4 months 4 cycles 2 months also the room the tank is in beads to be completely dark no ambit light

 

[tsellers]

Interesting experiment idea. I recently switched to LED's as I was part of the eshine group buy. I am currently acclimating my tank to the new LED fixture. After reading Dylan's post about two photo periods I decided to set up two photo periods during acclimation. Current photo period is below. I plan on ramping up the (blues/whites/uv's) photo period 30 min to 1 hour per week depending on how my corals are doing.

6am-7am (blues)
7am-8am (blues/whites/uv's)
8am-9am (blues)

6pm-7pm (blues)
7pm-8pm (blues/whites/uv's)
8pm-9pm (blues)