Lower light coral growth discussion

[tosiek]

I stumbled into some theoretical discussion on all of this maybe 2-3 years ago on one of my reef expeditions through Connecticut. Made my ears perk up and heard alot of tidbits around through other reputable reefers for a while after and then haven't heard anything. With the new LED craze thats sweeping through I've heard alot of talk about "better growth with LED's vs MH's" and wanted to throw it out for discussion because I feel it further explains why people are seeing better growth from LED's. I can't get into actual numbers or experiences because this has been all theorycrafting for me and listening to people.

I started hearing about it all when all the deeper water SPS started coming in. Proper low light conditions are known to give alot of coral that fluoresce and "color up". When you get that perfect balance of light your coral and the symbiotic photosynthetic bacteria balances out between what energy is produced to be used by the bacteria and coral for normal functions without overproducing bacteria that need to be expelled thus stressing and draining the coral and possibly hindering growth? From what I last remember, coral color and growth both increased in lower lighting compared to the typical aquarium placement and setup.

This is the basis of the theory. Providing the proper amount of light which everyone does to a degree. The problem is that coral tend to do "good" in variable conditions. Its colorful, grows about an inch in 2-4 months, polyps are waving around. Everyone is happy. But what is the proper growth and color for these corals? Low light tends to bring out a better fluoresce and an overall healthier coral, so are we over illuminating our coral? Why are people seeing increased growth and color from their new LED's?

There are plenty of people with 400w MH's and coral placement the same as someone with 250w. These corals are getting more PAR yet growth and color are the same. Im not going to get too into it but leave the rest to discussion. If im overthinking or wrong with anything let me know.

Anyways, I really want to see Tyree's presentation on coral and light that he has but I can't read or download a copy. Maybe someone can chime in on it and seen it firsthand.

 

[batt600]

Well thay say leds are the closest thing to natural sunlight. That would explain the grow and the more vivid color you get from leds

 

[tosiek]

Who said LED's are the closest thing to natural sunlight?

 

[TRIGGERMAN]

I have used LEDs and heard from others using them that there was much LESS growth than mh. I like the look of LEDs but I really don't think you can compare ANY LED to a 20k 400w radium or even a 250w as far as growth is concerned. I've had discussions for hours and hours with people who have used mh t5 and LED many members here and other reefers as well. I honestly think that LEDs haven't been used long enough for people to say they work better or they are the closest thing to natural sunlight, those are VERY bold statements. LEDs also lose brightness over time.every 6 months- a year I believe. With MH or T5 you change the bulb and it's back to where it should be. With LED's there is no bulb replacement just expensive price tags and you use them as long as they last.

 

[prattreef]

Where is there any real evidence of increased growth or coloration from using LEDs--hyper florescence from overly blue light aside?

IMO, yes at times we do over-light our systems and many corals do better under lower light. Some, however really thrive in as much light as you can possibly give them.

 

[House of Laughter]

Where is there any real evidence of increased growth or coloration from using LEDs--hyper florescence from overly blue light aside?

IMO, yes at times we do over-light our systems and many corals do better under lower light. Some, however really thrive in as much light as you can possibly give them.

I agree - this little research project would be, without a doubt, impossible to build the proper controls around to develop a scientific position on.

That being said, I have an LED system over my propagation trough. I also have 2 - 250w DE 14k metal halides - the results are varied - quite frnakly, keeping this thread on-point is conter-intuitive to using LED's (with the exception of the ones where you can control their intensity in specific time frames [ACAN Lighting]) Since deeper water corals or lower light corals is in direct opposition of the industry standard "pitch of par" as to the reason why you should switch to LEd's in the first place.

Completely counter to that arguement, my ponape birdsnest is growing best under LED's shaded by the trough's euro-bracing - when I had it there under halides, it suffered in growth and color. So now, I have a less light demanding coral doing better under the same shaded conditions with a light with more PAR - now what?

House

 

[batt600]

Who said LED's are the closest thing to natural sunlight?

Here you go read this http://www.gwarehouse.com.au/node/987 . Its also depends on what leds are you using alot of people are having great color and growth with cree 3w led and since the XPE and XPG came out there is even better growth. If you go to reefcentral theres a post just for led for growth and man a big diffrence from MH and T5 growth. The 1w led are were the slow growth your hereing about from leds. growth really doesnt come from lights it comes from a constant level of par staying in check and the right salinty If you dont have those in check it doesnt matter what light you have you will alway have slow growth.

 

[Chris Jury]

I'll skirt the LED discussion as I have little practical experience using them on tanks, and others are better to comment there. However, as Randy says above, some corals do definitely get overlit in tanks, and some will take as much light as we can, practically speaking, give them.

One of the big problems with discussing lighting needs for corals is that folks so, so often oversimplify IME. There is a huge amount of diversity in the photosynthetic properties of various zooxanthellae (these are dinoflagellates--"algae"--not bacteria), and this diversity is further modified by the corals themselves. For instance, whether a coral is an "sps" or "lps" tells you squat about it's lighting needs and tolerances.

For example, the most abundant corals around Coconut Island, where I work, are Porites compressa (a branching Porites species) and Montipora capitata (encrusts, branches, and forms plates, depending on environment and maaaaaybe genetics). Both species grow from the surface of the water to the base of the reef (~50 ft at the deepest). Hence, both can survive in really bright light (~1200 umol photons/m2/s--about 1/2 the intensity of surface sunlight), and relatively dim light (<100 umol photon/m2/s). However, if you measure rates of photosynthesis, growth, proxies of photodamage, etc. you'll see that the Porites just gets happier and grows faster the more light you give it, up to at least 1200 umol photons/m2/s. To put into perspective, that's the light intensity you might see 6-10" from a 400 watt metal halide bulb. It's bright, and way brighter than we generally expose corals to in captivity. On the other hand, the Montipora maxes out growth, photosynthesis, etc. in the neighborhood of 300-500 umol photons/m2/s, and gets progressively less happy at brighter light levels. We can easily reach values of 300-500 umol photons/m2/s with halides in captivity. They're both "sps" and they can both survive and grow in suboptimal light conditions, but they have very different preferences.

Different corals really do have very different preferences. Since a lot of the equipment that would help to figure this out is a bit pricey for the average hobbyist (say $18K for a PAM fluorometer), it takes a little bit of educated guessing, and trial and error. Some corals are going to do the things we want them to do best in really bright light, and others are going to freak out, not do what we want, and potentially die. This is one reason getting captive-grown frags from other hobbyists over wild-collected colonies can be a good idea: a lot of the trial and error is already figured out

 

[Chris Jury]

p.s. I will add, however, that 1) LEDs are really not that close to sunlight in spectrum, and certainly aren't closer than halides or fluorescents in general, 2) there's little reason to think that a spectrum closer to sunlight is preferable--if it were, almost no one would have any success because all of the lights we use tend to be a departure from sunlight, and 3) LED-lit tanks aren't necessarily dimmer than those lit by fluorescents, or halides.

 

[Alex]

LEDs also lose brightness over time.every 6 months- a year I believe. With MH or T5 you change the bulb and it's back to where it should be. With LED's there is no bulb replacement just expensive price tags and you use them as long as they last.

Triggerman this is not correct as many here can explain. As we know all lighting loses intensity, including the "almighty" LED bulb, however just like MH and T5 bulbs they can also be changed out. Ask anyone who has an AI fixture how easy it is to just open this unit up and exchange the components. This is one of their selling points, upgradeability. Also ask wingo what happens when a chip in a string of LEDS is bad, It has to be changed out. Now, it may not be easy to change out an LED chip like a MH or T5 bulb but it is possible. Now the question is would an individual change it out every year or wait more time in order to achieve a constant lighting regiment. But this would also be true with any bulb. The person would have to have a color meter as well as a par meter in order to change out the bulb when it starts to lose par and or color spectrum.

 

[TRIGGERMAN]

Actually it is correct and if you want to bring up Wingo and his LED expertise he said something in another thread a few days ago saying the same thing I just said about them losing strength. I believe it's something like 12-14% the 1st year and like 7% every year after? I'm not 100% sure but in your 1st 2 years you are losing approximately TWENTY PERCENT! I'm sure he will chime in sooner or later. I don't know about AI's I have Acan on my biocube and another brand sitting in my living room I forget what it is I haven't used them yet. Most LED fixtures you cannot switch out bulbs and replacing them is not going to be an easy task. Like I said it's a hell of a lot easier to swap an mh or t5 bulb and it will always have the same par the 1st year the 2nd year the 3rd year and so on. You are also talking about 1 particular fixture versus the world. LOL Just because there is ONE LED fixture that you can change bulbs on doesn't mean that what I said is wrong it just means there's 1 example that is fixable.

 

[bizzarro]

According to CREE specs sheets, they claim at least 70% output after 50k hrs. If you run the lights at 8 hrs a day, you'd be running them for 17 years before you need to change them.

I'm sure the setup and design plays a role in their longevity as well.

 

[TRIGGERMAN]

Most lights that are programmable have a 24 hr time setting sunrise sunset moonlight day actinic whatever . Usually you hear 5 years on LED's If you add up 24 hrs a day x 365 it's almost 9,000 so making it pretty close to the 5 year life expectancy. I guantee people won't have the same LED light in 5 years and if they do it would be running like CRAP. I guess only time will tell though.

 

[Alex]

The post is about lower light coral growth not about the ease of bulb exchange or about AI lights, I use these as an example. Now you know as well as I do that in a determined mind easy or hard is not a problem. If reefing where easy most of us would have other things to do, but as it is we love reefing for the challenge, the beauty and other factors. So what I'm saying is that changing a bulb is not a problem for someone who has invested hundreds of dollars in their reef, whether MH T5 or LED. When the optimum lighting is being sought change is our first consideration.

 

[Alex]

Now speaking about low light corals, take Acans as an example. Different light sources will bring about different colorations in acans. As seen by the beautiful multicolor frag that was just purchased and a month later turns to a completely different color under lets say MH.This is a complaint many of us have when dealing with acans, the change of color once we bring the frag or colony home. I would think this to be a great example of low light corals adapting to the lighting.

 

[Aqua Pro Builder]

Actually it is correct and if you want to bring up Wingo and his LED expertise he said something in another thread a few days ago saying the same thing I just said about them losing strength. I believe it's something like 12-14% the 1st year and like 7% every year after? I'm not 100% sure but in your 1st 2 years you are losing approximately TWENTY PERCENT! I'm sure he will chime in sooner or later. I don't know about AI's I have Acan on my biocube and another brand sitting in my living room I forget what it is I haven't used them yet. Most LED fixtures you cannot switch out bulbs and replacing them is not going to be an easy task. Like I said it's a hell of a lot easier to swap an mh or t5 bulb and it will always have the same par the 1st year the 2nd year the 3rd year and so on. You are also talking about 1 particular fixture versus the world. LOL Just because there is ONE LED fixture that you can change bulbs on doesn't mean that what I said is wrong it just means there's 1 example that is fixable.

Once again, please note the numbers I quoted Reefman before was for ONLY for a couple diodes I tested over 3 years in a rudimentary setup thus they are not representive of any real life fixture-a little better or worse handling of the cooling paste will change the results greatly. BTW, the numbers were the first year is about 12% degradation and then some what about 3% each the following 2 years. The diodes are lited 7/24 for the whole duration with only intermitant shut-offs during moves or such.

Now back to the contradiction of the growth experience when using LED. I think a lot of the issue of faster/slower growth experience with LED is affected by the angular property of LED. In couple seminars, I demonstrated the ANGLE of the beam is more relevant towards the par rating than distance from the light source in LED technology inreference to MH or PC. Thererfore, when using LED, there are areas that we thought to have high par may actually with low par while areas where we thought has low par turns out to have high par. That's many implementation of the LED fixture's intensity is very spotty. In one experiment, I tested the data for a member(somethign like ReeferNYC or NYreeferxxx) here which I posted the results before in a thread, showed that the corner of the tank has a higher par value than an area 3/4 down the tank and about 9-12inches closer to the middle. This illustrate the dependence on angle of the beam more than the distance from the LED source.

 

[prattreef]

Once again, please note the numbers I quoted Reefman before was for ONLY for a couple diodes I tested over 3 years in a rudimentary setup thus they are not representive of any real life fixture-a single miss handling of the colling paster will change the results greatly. BTW, the numbers were the first year is about 12% degradation and then some what about 3% each the following 2 years. The diodes are lited 7/24 for the whole duration with only intermitant shut-offs during moves or such.

Now back to the growth issue. I think a lot of the issue of faster/slower growth experience with LED is affected by the angular property of LED. In coupel seminars, I demonstrated the ANGLE of the beam is more relevant towards the par rating than distance in LED technology than MH or PC. Thererfore, when using LED, there are areas that we thought to have high par may actually with low par while areas where we though has no low par turns our to be high par. That's may implementation of the LED fixture's intensity is very spotty. In one experiment, I tested the data for a memebr here which I posted the results, show that the corner of the tank has a higher par value than an area 3/4 down the tank and about 9-12inches closer to the middle. This illustrate the dependence on angle of the beam more than the distance from the LED source.

That is very interesting Wingo.

 

[Alex]

Once again, please note the numbers I quoted Reefman before was for ONLY for a couple diodes I tested over 3 years in a rudimentary setup thus they are not representive of any real life fixture-a single miss handling of the colling paster will change the results greatly. BTW, the numbers were the first year is about 12% degradation and then some what about 3% each the following 2 years. The diodes are lited 7/24 for the whole duration with only intermitant shut-offs during moves or such.

Now back to the growth issue. I think a lot of the issue of faster/slower growth experience with LED is affected by the angular property of LED. In coupel seminars, I demonstrated the ANGLE of the beam is more relevant towards the par rating than distance in LED technology than MH or PC. Thererfore, when using LED, there are areas that we thought to have high par may actually with low par while areas where we though has no low par turns our to be high par. That's may implementation of the LED fixture's intensity is very spotty. In one experiment, I tested the data for a memebr here which I posted the results, show that the corner of the tank has a higher par value than an area 3/4 down the tank and about 9-12inches closer to the middle. This illustrate the dependence on angle of the beam more than the distance from the LED source.

Wingo, can this be adjusted (Par ) with optics or does optics only control angle of light ? Like using reflectors to adjust the angle of light on MH.

 

[lfsmarineguy]

You can't make a blanket statement about all LEDs losing a certain % of "strength" for each of the first few years based on a single unit Wingo tested. There are just too many types of LED, differently built units, and even photo periods to even come close to a statement like that. Dimming an LED can prolong useful life and running a unit at 2% for moonlights is not the same as running it at 100% during the high point of the period.


As for the growth, we know that corals have a window of tolerances (in regards to the light portion of this). They occur at a range of depths which could represent different types of aquarium lighting. Whenever I add a coral I usually wedge it into the rock around where I want it or use just enough glue to hold it so it can be moved later. If it isn't doing as well as I would like I move it somewhere else until I find a good spot for it. Sometimes even if you move a frag a few inches in any direction a new growth pattern can emerge or growth can accelerate. I'm inclined to say that I don't think it's the coral as much as the tank. If you take a frag and put it in another tank in the exact same spot I doubt it would respond the exact same way every time. Flow and water quality play a huge role and I think they trump the importance of light if they can be kept at an optimal level for the specimen. Light is only present for a portion of the day but the coral is always in contact with the water and currents. I'm not saying light isn't important, just that there are other more important factors.

 

[Aqua Pro Builder]

Wingo, can this be adjusted (Par ) with optics or does optics only control angle of light ? Like using reflectors to adjust the angle of light on MH.

The optics change the PAR when they change the angle of the light beam.