Let's talk Photoperiod

[JasReef]

It's Monday so let's get a good conversation going for the week.

I have been doing some reading on how long people are leaving their lights on (photoperiod). There are some great articles out there. This one got me thinking. https://reefs.com/2013-2/light-intensity-requirements-of-shallow-tidepool-coral/

Some believe in a more natural approach, mimicking the natural photoperiod of places that our corals come from (Australia, Bali, Fiji). This group even follows the season to increase or decrease the amount of time they leave the lights on.

Some believe in a long photoperiod all the time. 10, 12 to even 15 hours is not unheard of. It seems a majority of reefers follow this approach. The more the better, right?

The last group follows an interesting idea. They believe in a process known as photo-inhibition. This is basically a light induced reduction in the photosynthesis of our precious zooxanthellae. The idea is the corals get stressed from too much light so they shut down. So they run the lights for maybe 6-8 hour range.

Keep in mind there is very rarely a definitive right or wrong when it comes to reefing and what works for one may not work for the other. We all do so many different things to our tanks and we all see successes and failures as a result. Photoperiod is no exception.

So with these concepts reduced to the very basics where do you think you fall on the spectrum? And more importantly, why?

[rosslonghorns]

I'd be interested to see what duration average everyone is using.

I run blue from noon to 8 pm and white from 1:30pm to 6:30pm. So overall duration of 8 hours with whites/blue combo only running for 5 hours.

I haven't seen any negative impact for the almost a year it has been setup so haven't changed anything.

[mdavis735]

My opinion on this is the same as it is with a lot if other subjects in reefing. I believe our corals adjust to the parameters we set for them. I think they will thrive in many different conditions. I feel like change and instability is more detrimental to them than the actual value of a certain parameter. Don't get me wrong. There are obviously ranges that are acceptable and not acceptable in most tank parameters, but within those guidelines I think stability is much more important than the number.

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[Sascha D.]

I'm using 4 LED fixtures at 100% blues 60% whites

On at 11 a.m.

Off at 9:20 p.m.

No ramping up or down

[FarmerTy]

My overall light is about 8 hrs with a combination of T5 and LED lights. I'm a believer in the photo-inhibition discussed by Dana Riddle, he actually did a talk on it at one of the C4's. Great data and great test he conducted. In spite of the data, I still run 8 hrs but that's more for my viewing pleasure then for the corals energy needs.

[+FluxCapacitor]

What about intensity?

I have 20k's in the morning for an hour or two and then it goes to 12k and 10k for most of the day then back to 20k's before fading off for the night. The 12 and 10k spectrums are @100% on my AI Primes.

[JasReef]

I'd be interested to see what duration average everyone is using.

I run blue from noon to 8 pm and white from 1:30pm to 6:30pm. So overall duration of 8 hours with whites/blue combo only running for 5 hours.

I haven't seen any negative impact for the almost a year it has been setup so haven't changed anything.

It's always good to compare notes on things like these. I am interested as well.

My opinion on this is the same as it is with a lot if other subjects in reefing. I believe our corals adjust to the parameters we set for them. I think they will thrive in many different conditions. I feel like change and instability is more detrimental to them than the actual value of a certain parameter. Don't get me wrong. There are obviously ranges that are acceptable and not acceptable in most tank parameters, but within those guidelines I think stability is much more important than the number.

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I agree that they corals basically set to parameters in our tanks however I do not feel like we can alter photo inhibition in a way that can be beneficial to both growth and color. It seems less could be more in this situation. Stability is a non negotiable no matter what you refer to as it applies to most reef parameters. The relationship between zoo and light has a little more leeway than most because of the stress causing other processes to occur in lou of photosynthesis, such as browning out for protection.

I'm using 4 LED fixtures at 100% blues 60% whites

On at 11 a.m.

Off at 9:20 p.m.

No ramping up or down

I think if we did a bell curve 10 hours would be at the top of the curve for most of us.

My overall light is about 8 hrs with a combination of T5 and LED lights. I'm a believer in the photo-inhibition discussed by Dana Riddle, he actually did a talk on it at one of the C4's. Great data and great test he conducted. In spite of the data, I still run 8 hrs but that's more for my viewing pleasure then for the corals energy needs.

The article I need to read a couple more times but it is compelling science so my brain needs to run around the block a couple of times to catch up with it.

[JasReef]

I have 3 Ai Prime Hds that run all blue overdriven no white,re, or green. They come on at 10 and stay on until 10. I look to add color with these. My 2x250w metal halides come on separately. 1 comes on at 10am till 1500. 2 comes on at 1200 till 1700. My 2x 80w T5 comes on from 1100 to 1800. Thats 8 hours of led blue stay on from 1100 to 2200. I'm slowly changing these times down as I would like to see an effect on coral color specifically getting rid of some brown parts.

What type of lights are important as is the intensity of the lights along with time we try to experiment and see what colors we can bring out from under the browns.

This is good fun stuff!

[Sascha D.]

I'm using 4 LED fixtures at 100% blues 60% whites

On at 11 a.m.

Off at 9:20 p.m.

No ramping up or down

I think if we did a bell curve 10 hours would be at the top of the curve for most of us.

At the intensity of my lighting this is the highest photo period that I could run. I have tried a 12 hour period before, but the corals begin to brown out and the algae growth is off the charts. I'm guessing the corals produce a great number of zooxanthellae and that browns out the color. I wouldn't mind reducing the period if it would benefit the corals.

[JasReef]

I'm using 4 LED fixtures at 100% blues 60% whites

On at 11 a.m.

Off at 9:20 p.m.

No ramping up or down

I think if we did a bell curve 10 hours would be at the top of the curve for most of us.

At the intensity of my lighting this is the highest photo period that I could run. I have tried a 12 hour period before, but the corals begin to brown out and the algae growth is off the charts. I'm guessing the corals produce a great number of zooxanthellae and that browns out the color. I wouldn't mind reducing the period if it would benefit the corals.

Yep, I am getting really good growth but the colors just aren't as good as I know they can be. I reduced the highest intensity time down to see if this is it. At least we know less light won't likely cause a coral to die.

[Timfish]

Delbeek and Sprung's The Reef Aquarium, Vol III, has some good charts showing light intensity reefs get at different depths. Reefs get only a few hours of max intensity when the sun is directly over head and intensity drops off quite dramaticly before and after (it's not a simple ramp up and down). The comments about photo inhibition and adaptability I think show the balance we need to strike between what we want, what our corals want and what our corals will adapt to. (It seems to be forgotten or never passed on to newbies these bright colors we like in our corals are the corals trying to adapt to less than ideal lighting conditions.) The idea that "more is better" will end up killing corals. Besides Dana's presentation Ty referred too and can be seen here, Dana also has a whole series of articles on Advanced Aquarist. For my tanks, I would never run lights longer than 12 hours and like Ty prefer to stay around the 8 hour mark.

[Juiceman]

My LEDS come on at 7:00 AM

Ramp up to 75% at 2:00 unitl 5:00

Ramp Down from 5:00-10:30

T-5s come on at 11:00-11:00 ramp up to 100%

T-5s Ramp Down at 8:00-9:00 off

i'm only at full intensity for 3 HRS which is 100% T-5 and 75% LED

Total photo period 7:00am - 10:30 PM

[Neon Reefer]

1st of all if we are not measuring or have measured at various depths the intensity of light with a meter than we are really guessing at what we are doing. This makes it hard to quantify just how much light we are providing.

Length of time is only one of four major categories affecting light and corals

First there is water clarity, second the color spectrum (heat) provided, third is the intensity of light provided and fourth is the length of time the light is provided.

The full combination of all 4 of these contribute to the final answer to determine the length of time the light should be applied.

One could look at my system and run the same lights at the same time length and get differ results from the same coral. Just as if my water clarity changes over time so does the intensity of light provided

I think the real indicator is your coral, They will tell you much of what we need to know if we know what to look for. I know some of these indicators and would share but I don't want to hijack the conversation.

Maybe we need a a forum conversation on this " What are our Corals trying to tell us."

[Sascha D.]

I looked into my tank to discover what my corals were trying to tell me. One one had a sign that said "Zooxanthellae Lives Matter" and another one had a little sign that read "Mike Paletta for President". I have to say that I agree with both.

[JasReef]

Delbeek and Sprung's The Reef Aquarium, Vol III, has some good charts showing light intensity reefs get at different depths. Reefs get only a few hours of max intensity when the sun is directly over head and intensity drops off quite dramaticly before and after (it's not a simple ramp up and down). The comments about photo inhibition and adaptability I think show the balance we need to strike between what we want, what our corals want and what our corals will adapt to. (It seems to be forgotten or never passed on to newbies these bright colors we like in our corals are the corals trying to adapt to less than ideal lighting conditions.) The idea that "more is better" will end up killing corals. Besides Dana's presentation Ty referred too and can be seen here, Dana also has a whole series of articles on Advanced Aquarist. For my tanks, I would never run lights longer than 12 hours and like Ty prefer to stay around the 8 hour mark.

Dana Riddle is who got me thinking about all of this. The link I provided is one of his. I agree more is better will end up killing corals. I like the idea of the natural approach but it seems very involved and complicated. I suspect we will get the most out of our corals with around an 8 hour with a peak in the middle.

1st of all if we are not measuring or have measured at various depths the intensity of light with a meter than we are really guessing at what we are doing. This makes it hard to quantify just how much light we are providing.

Length of time is only one of four major categories affecting light and corals

First there is water clarity, second the color spectrum (heat) provided, third is the intensity of light provided and fourth is the length of time the light is provided.

The full combination of all 4 of these contribute to the final answer to determine the length of time the light should be applied.

One could look at my system and run the same lights at the same time length and get differ results from the same coral. Just as if my water clarity changes over time so does the intensity of light provided

I think the real indicator is your coral, They will tell you much of what we need to know if we know what to look for. I know some of these indicators and would share but I don't want to hijack the conversation.

Maybe we need a a forum conversation on this " What are our Corals trying to tell us."

Do you think a lux meter at surface level would suffice or a par meter at different depths throughout the system? While I agree 100% a light meter will give you more quantifiable results I also believe that watching our corals as you describe will give us those results, it just will take longer to "dial in".

It is hard not to talk about other factors such as chemistry or flow because they are all factors that contribute to healthy coral in our tanks.

As far as clarity of water and light penetration what do you have in mind? What I understand is that turbid water will have lots of suspended particles in the water that can have an effect but I am not so convinced that running carbon to stop water from yellowing has much of an effect. I have looked for info on the yellowing effect and it mostly points back to marketing for carbon products and the aquarist wanting a clearer look."The intesity of light above the surface of a reef can be as high as 130,000 lux. The actual amount of intensity that penetrates the surface of the water can be about 70,000, with maybe only 15,000 lux actually reaching the 10-15 meter mark." With this in mind the lux in our less than 1 meter deep tanks is quiet significant and probably not effected by some particles or yellowing in the water.

Intensity definitely has an impact on the photoperiod as Timfish stated above in that corals in the wild only get a few hours of full intensity during the day. If we pound our corals all day with max intensity I think it would fall in the more is better fallacy.

I guess I assumed that most reefers will have a light that falls into the right color spectrum for coral growth. Because of the way light penetrates water the blue spectrum would be the most natural but may not provide the most growth.

[Neon Reefer]

Yes spectrum is important. If using an array of LEDs where much of the white is warm compared to whites that are brilliant, you have a difference of penetrating light. So if you run a 15k spectrum over your tank you should in theory get better penetration than say 10K. As far as turbidity goes, one might be surprised how much light can be deflected by those millions of tiny particles. And if I understand the theory of light (which I probably do not) then yellow is simply reflection yellow spectrum which is far less important to our corals much like greens. A surface measurement tells us much less than the PAR meter at particular depths will tell you. Although PAR at the surface or LUX converted to PAR at the surface will tell you exactly the same thing. How much light intensity you have at the surface. However I doubt if you have coral growing just above the water line.

As far as my vote> Sorry Mike

[Peter Gott]

I like to run my actinics stupidly long, like 12-14 hours, but leave on the main lights about 6 hours.

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[Sascha D.]

I like to run my actinics stupidly long, like 12-14 hours, but leave on the main lights about 6 hours.

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Why do you like this schedule and how powerful are the lights?

[Peter Gott]

I like to run my actinics stupidly long, like 12-14 hours, but leave on the main lights about 6 hours.

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Why do you like this schedule and how powerful are the lights?

For two reasons--one, I follow my own accidentally-adopted theory of photo-inhibition; and two, aesthetics. This began years ago when I first got into the hobby and didn't know much about what I was doing. LEDs weren't a thing yet, and I couldn't afford (and didn't like) metal halides. Before I even got into T5s I was just using a lot of HO (my VHO) T8 fluorescent lights over a shallow reef (30 long). I did a lot of reading, but I found that I learned more by watching my coral. My challenge was that I kept odd hours, but wanted to see my corals; I also loved watching them fluoresce. So by process of trial and error, I ended up using the actinics about 14 hours a day, and then white lights for more PAR about 6 hours a day. I believe that original tank had two of the purple actinics that I left on the full 14 hours, two regular white grow lights, and two that supposedly had actinic in the mix and put off a lovely pinkish white light. None of these were expensive lights, mind tou. Then I discovered T5s (again, cheap ones) and added the bright blue actinic to the mix. For a while I had those on a 10 hours, between the 6 and 4. Then I scaled it back to all lights on for six, and one purple T8 and one blue T5 for the full 12. As I began expanding and growing out coral frags during my brief stint as a local "coral farmer," I repeated this setup across several more aquariums, all long and shallow. I had one each of the purple and blue on each side of the aquarium, so l tried to mimic the sun traveling through the sky by having the right-hand pair on for six, during the latter three hours of which all the white lights were on as well; then I switched the actinics on the left side on and turned the right side off and repeated it in reverse. I gradually replaced most of those with T5s and got better growth, but honestly still preferred the colors I got from the old cheap T8s...

Next I got really into picos, especially 1-2.5 gallons with deep sand beds and under gravel filters run by air pumps. At this point I could afford supplemental LEDs for actinic blue accent, and I use CFLs that were half the white and half the purple actinic as the main six-hour-a-day source. I played around with keeping them on longer, but it seemed to stress the coral; so I stuck to the same short-photo-period with super-intense lights and longer photo period with less intense actinics just for aesthetics.

My very favorite tank ever ran a slightly different schedule. With this one I had a Kessik A150WE Ocean Blue; a custom PAR38 bulb with one red, one green, two whites, two UVs and four royal blues; and two supplemental actinic blue LED strips. With this one I turned on the PAR38 in the morning and let it run for eight hours. The Kessil I ran for the middle four of that, and then the actinic blue LEDs turned on at the same time as the Kessil and ran for 10-12 hours, depending on my mood (and when I went to bed). So overall, there was a lot of visible light for the coral, but only a short period of intense light. Color and growth was phenomenal, and I only ever had one problem with algae, when I had to disconnect the refugium for a bit.

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[Good Greef]

On this note, since I started running my AP700 1 yr ago, ive also run a longer photoperiod from 630am - 830pm. Maxing out at 80% intensity at 11am for 3 hrs.

Ive gotten good growth on about 70% of my corals. But it seems like a few of them just stopped growing, most notably a red monti cap and a Jedi mind trick, which notoriously both are faster growers.

If I want to try and reduce my photoperiod from 14 hrs to 10 hrs for example, is this something I should do gradually bc I would think it wouldn't do too much? Perhaps I would get a less paler color in all my reds, which also seems to annoy me.

Thanks!

[JasReef]

I would just change them from 14 to 10 but if you want you drop an hour off every 4 days for two weeks.