Longer Less Intense Lighting versus Shorter More Intense Lighting: Which is better?

[revhtree]

Longer Less Intense Lighting versus Shorter More Intense Lighting

There may be no science to any of this or maybe there has been a huge study and I have no idea! But I was thinking about this the other day and wanted to get your thoughts on it. Several months ago I decided I wanted to keep various types of coral in my tank (other than acros) so I decided to raise all the lights about a foot higher off of the water. I didn't touch the intensity or the amount of time that the lights stayed on or stayed off. The other day I decided to extend the time the lights were on by a couple of hours and that's what got me thinking. So let's talk about it!

1. Which do you think is better, a longer photo period less intense lighting or a shorter photo period with more intense lighting?

2. Do you think there is a benefit to either one of these ways and if so what would they be?

image via @apt220

 

[T-J]

With no scientific backing, I'm saying longer, less intense. No different than how I'd prefer to eat: over a longer period of time, but smaller meals. I don't think I'd be happier with one GIANT meal versus food throughout the day.
Also, if the light gets too intense, it could still cause bleaching issues (I think).

 

[revhtree]

With no scientific backing, I'm saying longer, less intense. No different than how I'd prefer to eat: over a longer period of time, but smaller meals. I don't think I'd be happier with one GIANT meal versus food throughout the day.
Also, if the light gets too intense, it could still cause bleaching issues (I think).

That's a great analogy!

 

[saltwaterpicaso]

i have actually done this becouse i do not own a par meter and was to lazy to rent one. i ran my kessils at 50 percent for 8 hours a day for a few weeks then eventually 12 hours the tank suffered even with the extension. i then went to 75 percent over the course of 2 weeks at 8 hours and things greatly improved with color and growth. then i tried 100 percent for 6 hours a day and even with acclimation it was just to much. i think at 100 percent even for 2 hours would be to much and aggrivate certain corals. so i would say once you find the sweet spot for your lights you can go as long as you want with the photo period.. not really sure if this helps was just my findings. i also did this with my radions and same finding.

 

[revhtree]

i have actually done this becouse i do not own a par meter and was to lazy to rent one. i ran my kessils at 50 percent for 8 hours a day for a few weeks then eventually 12 hours the tank suffered even with the extension. i then went to 75 percent over the course of 2 weeks at 8 hours and things greatly improved with color and growth. then i tried 100 percent for 6 hours a day and even with acclimation it was just to much. i think at 100 percent even for 2 hours would be to much and aggrivate certain corals. so i would say once you find the sweet spot for your lights you can go as long as you want with the photo period.. not really sure if this helps was just my findings. i also did this with my radions and same finding.

Thanks for the input!

 

[revhtree]

Come on peeps! What do you think on this one?

 

[Clownfish_Boy]

My FO requires light for illumination only, so it does not have to be as powerful as in a reef.

 

[highest_tides]

I've found, I run my channels at a lot lower of an intensity than most I talk with and for a 12 hour period. So on the longer end but nothing different from what I've adjusted the tank too and it is thriving. I only run 20% intensity blues and 1% on whites with Viparspectra's right now. I'm slowly working my way up.

 

[Wiskey]

I really hope lower light for longer is the way to go! I'd have my tank on 24/7 if I could. I would much rather have half the light for 12 hours, than really bright light and only enjoy the tank for 6.

Whiskey

 

[Ron Reefman]

I believe coral zooxanthellae can only do photosynthesis with fairly intense lighting. Think 10am through 3pm out on a reef in the tropics. And they can only do photosynthesis for between 5 and 8 hours and then they shut down.

 

[sp1187]

guess it depends somewhat on your lights, tank depth, where the inhabitants are from geographically.
TMC AquaBeam 2000
30" deep tank
equatorial long hours, intense sun

12 hours on/off
4 hour ramp up
4 hours 100%
4 hours ramp down

I'm no scientist, but I did sleep at a Holiday Inn last night.

 

[Roosterjack]

Is it possible to vary the output from day to day, and/or seasonally? Nature is the best role model, and the sun’s intensity on a given reef is likely not the same from day to day.

 

[sp1187]

Is it possible to vary the output from day to day, and/or seasonally? Nature is the best role model, and the sun’s intensity on a given reef is likely not the same from day to day.

my lights have a "cloud" program. when I have it on, the tank will go random shade, from left to right, across the tank. haven't used it in a while though. novelty wore off.

 

[sp1187]

Come on peeps! What do you think on this one?

me thinks you still owe a pic of your tank on a previous "Quest o Day."

 

[WVNed]

I keep the lights on during the hours I want to look at the tank. I make the intensity work out.

 

[KrisReef]

I’m too cloudy in mind to recap accurately the results found from previous studies (not done by me!)
I agree with RonReefman .
Would add that folks have done experiments doing 2 photo periods/day using “intense” lighting (maximizing photosynthesis in coral) trying to see if they could improve on growth vs the More natural daytime lighting cycle on wild reefs.

I believe they did find slight improvements? Otherwise I don’t have any more light to shead on the topic.

 

[Grabble]

There have been a number of interesting papers done on this subject. The reality is that with modern lighting most corals will receive more than the required level of light even on a photo period as short as 6 hours, essentially we're over-lighting them. Higher intensities can cause light-shock which in turn can lead to bleaching/reduction in coral growth. Equally, extremely overly prolonged use of lighting (20+ hours a day) can lead to a different form of light-stress with the same bleaching/reduction in growth seen.

So which is better? Well it rather depends, what you're keeping, and how deep you're keeping it in terms of light sensitivity. But assuming you don't over sensitise the coral with light to induce stress the reality is that the limiting factor on coral growth is far more likely to be water flow, nutrient load and the availability of key nutrients and trace elements.

To answer the original question there's no real difference to the coral in terms of light period, or intensity so long as you don't push it too high and cause stress so light them for the length you feel comfortable with to view them.

 

[Ef4life]

I voted not sure, but I would prefer to run them longer for the simple fact is I like to look at my tank, it’s not really fun To look at having the lights on only for a short period. My lights on my main reef start up at 7 am and stay on until 10pm, but I have a Very long ramp up cycle, About a 5hr period of full intensity, then a shorter ramp down cycle.

 

[ubasu]

I always get algae issues if I extend the lighting too long. 8+ hours....

 

[Dburr1014]

On My tank, less intense and longer time.
I have some hammers that are flourishing under those condition. I also have a few sps that are coloring up nicely.
I own reef breeder lights so I have the ability to ramp up and ramp down. I'm only at full spectrum for a couple hours, the rest is ramping time.