split lighting schedule

[zachtos]

Does anyone recall reading about split lighting schedules? I can't find the articles from the past but wanted to followup to see if anyone did some testing...

I have been running my tank on split lighting all summer and am not really sure if it affected growth all that much, it sure didn't hurt it though!

-5 hours morning = LIGHT
-6 hours afternoon = DARK
-5 hours evening = LIGHT
-8 hours night = DARK


Supposedly corals could only process about 4-5 hours of intense light at a time, then need about 4-6 hours to process it before they can start receiving more light... otherwise I guess it's wasted energy.

I like the new light schedule because the tank is on in the morning while I get ready for work, off while I'm gone, then on again when I return.

Split lighting also drastically aided my home cooling efforts on hot days since it's off during the hot part of the day (noon - 6pm).

I am upgrading from T5 overdriven to 400W MH and want to know if it's worth continuing this regimend w/ MH.

This is for sure an advanced topic that very few will know the answer to...

input?

 

[greenbean36191]

Supposedly corals could only process about 4-5 hours of intense light at a time, then need about 4-6 hours to process it before they can start receiving more light... otherwise I guess it's wasted energy.

No. Photosynthesis doesn't work this way. At any intensity at or below saturation, you get the same output for as long as the lights are on. It only gets bogged down after a few hours if the intensity is so high that it's damaging the photosynthetic machinery. In that case it would be much more beneficial to reduce the intensity rather than either shortening or splitting the photoperiod.

 

[zachtos]

Excellent reply. Does anyone happen to recall where that discussion thread is located or article?

In the mean time, I will stop the split light schedule.

One last question is related to the split schedule and heat. It is beneficial for myself (and I'm sure a few others) to run the split schedule during normal summer months to aid in cooling... BUT, does that hamper growth or should the growth be the same?

(not sure if it takes time for the coral to start performing growth)

*I'm also going from T5 to MH 400W soon, so I'm also unsure of if 10hours / day all at once is far too much (I think most people do 400W MH for 6-8hours/day?)

 

[EnderG60]

From what I have read and what I have seen, anything over 6 hours of light doesnt seem to affect anything but algea growth.

I thought about doing the split cycle to avoid using power durring on-peak hours, but decided against it.

I now usually have my halide on for 6 hours and then leave the supplimental t5's on for the rest of the time I want to be able to see the tank. Works very well and growth hasnt changed since I had my halide on for 12-14 hours a day.

That said when my chiller went out, I had my halide turn off when the temps got high, so for a good 4 months the lighting cycle was t5's on for 14 hours and in that time the halide would be on for an hour and off for an hour. Didnt see any change in growth there either.

 

[zachtos]

Interesting, I would love to see some other opinions or research indicating that a split light schedule for the hadlides won't effect growth one way or another. It would be nice to have the lights on in the morn/night, but off during the mid day when not home or hot out.

 

[Wrench]

I have no scientific reasoning or articles to back it up but split photoperiods suck.

I ran mine from 8-noon then from 6pm-10pm. I ran it this way for over a year and could never find the reason for my lack of growth. I switched the photoperiod to 2pm-10pm and things are growing like weeds. Color has improved as well.

 

[zachtos]

Anyone think a split photoperiod has an advantage for refugiums?

 

[OwenInAZ]

<a href=showthread.php?s=&postid=15681172#post15681172 target=_blank>Originally posted</a> by Wrench
I have no scientific reasoning or articles to back it up but split photoperiods suck.

I ran mine from 8-noon then from 6pm-10pm. I ran it this way for over a year and could never find the reason for my lack of growth. I switched the photoperiod to 2pm-10pm and things are growing like weeds. Color has improved as well.

I dunno, I run my lights from 4-9 AM and again from 7-11 PM. I haven't noticed anything not growing like crazy.

I think (although I also have zero science to support this) that it may depend on the type of lighting you're employing. I happen to be running 2x 400W 12K Reeflux. I don't know if it'd be different with T5's or something else. This may be another instance in which reefer-specific voodoo has more to do with it than actual science.

I definitely like the fact that I'm not "wasting" power when I'm not around to enjoy the scenery. The corals are growing, the clowns and cardinals breed constantly, what's not to like?

 

[Wrench]

Every system is different. It may work with yours. Mine didn't like it. I was running 250w Reeflux 12k.

 

[OwenInAZ]

<a href=showthread.php?s=&postid=15683864#post15683864 target=_blank>Originally posted</a> by Wrench
Every system is different. It may work with yours. Mine didn't like it. I was running 250w Reeflux 12k.

Right, like I said, it may be something to do with each reefer's voodoo. So let's not state categorically that "split lighting sucks."

 

[KarlBob]

<a href=showthread.php?s=&postid=15682371#post15682371 target=_blank>Originally posted</a> by zachtos
Anyone think a split photoperiod has an advantage for refugiums?

I don't know about a split photoperiod for refugiums, but I've read that it can be beneficial to run a reverse photoperiod in refugiums. While the tank lights are on, the refugium is dark, and for at least part of the time the tank is dark, the refugium light is on.

Some people run the refugium lights exactly opposite the display tank lights, so that a light is shining somewhere in the system 24/7. I have a hang-on-tank refugium, and some of its light spills into the tank (and into my bedroom), so I don't run the refugium light the entire time the tank light is off.

The supposed benefit of a reverse lighting schedule is maintaining a steady pH. Apparently, photosynthesis has a lot to do with pH and dissolved O2/CO2 levels in a reef tank. According to some people here at RC, the presence or absence of light has a greater effect on O2 and CO2 levels than other factors, like surface turbulence or a protein skimmer. When there are no lights, CO2 increases, and pH begins to drop. By running the refugium when the tank lights are out, we can maintain O2 production, and reduce the daily pH fluctuation in the aquarium.

In theory, a split lighting schedule could also smooth out daily pH fluctuations. Instead of one long dark period when pH drops, you'd have two (or more) shorter pH-dropping periods. Overall, this might mean that your daily maximum and minimum would be closer to each other than a tank without split lighting.

 

[ludiNano]

I have ran my tank like this since i set it up a year ago.

Display 6hrs ON : Refugium 6hrs OFF
then
Display 6hrs OFF : Refugium 6hrs On

then whole thing again.

Ive thought about switching to a regular lighting cycle to see if growth slows down at all. But i love the extended viewing too.

It does lessen your MH bulbs life, though with the extra fire every day.