The Red light spectrum...confusion

[kpiotrowski]

A recent article in advanced aquarist entiled "Red light negatively affects health of stony coral' , seen here http://www.advancedaquarist.com/blog/red-light-negatively-affects-health-of-stony-coral has many reefers taking from it exactly what the title says. Red light is will harm your coral :boom:


I'm going to quote a key point of the article, and let others chime in.

"the study reinforces the theory that corals use red light as their gauge for light intensity and regulates photosynthesis according to the amount of detected red light"

now think about that! and btw I have a diy 216 cree led with NO reds. I'm not comming for the "red" side. I'm on the corals side! and I say goooo red :cheer2: allthough impractical to really try to achieve in a LED fixture and provide full coverage at the right amount.

GO :fencing:

 

[mfinn]

I saw a thread on RC that talked about this issue ( or non-issue).
The title of the thread was " Red lights proven to do harm"

Not sure if the author was intentionally trying to start a controversy, or thought they would be "on the cutting edge" of information, but IMO the thread title was very misleading.
IMO the author of the article on AA was a "little" misleading.
In the article it says if TOO much red is used, then it can negatively affect coral growth. And the sturdy ( as far as I can tell) only used a single coral type, Stylophora pistillata .
Plus, the author was comparing the use of red light compared to blue light.

The quote from the article that I thought was key is this one.


Quote:
Note: red light is commonly found in proven lights such as Radium metal halides and numerous fluorescent bulbs as well as in wild reefs, so the idea is not that red light is necessarily harmful but that too much red light can have negative effects on how stony corals regulate photosynthesis.



In the article it showed a picture with 2 banks of light. On one side it looked heavy blue and on the other it has heavy red.
IDK, but when you go to extremes like that it's bound to produce negative results IMO.
I'm not very technical and I'm not really into sps. I'm just a common hobbist.

 

[tike]

I am with Marty on this one. I read the article and what i got out of it that TOO much red hampered growth. I have a LED unit with 3 red diodes and haven't experienced any growth issues at all. If you look at the photos in the article you see they used complete red light over the coral to conduct the experiment. I do find this a little misleading because who runs totally red light over their tanks?

 

[1guydude]

Lol o man. Thxs for the link. I cracked up last night when I saw this. The pic of the blue leds right next to all the red. Its priceless.
Silly scientists didn't need to kill a bunch of stylo to learn this....
D

 

[kpiotrowski]

I'm disapointed with the article's alarming title leads a person to belive that red light is bad.

The fact that the study included only one single coral, and that if you look at how much red light is absorbed from 0-25 feet depth in the ocean, then it is obvious that corals from different depths are used to varying degrees of red light ( red spectrum is the first to be absorbed) you have to consider other mechanisms the coral is using to farm zoox and keep happy amount of them in their tissue. the fact we have been able to take a coral from a depth of just 5 feet out of the ocean and expose them to unatural light as in metal halides that have a way different spikes along the curve than true full spectrum sun goes to show that corals addapt.

"the study reinforces the theory that corals use red light as their gauge for light intensity and regulates photosynthesis according to the amount of detected red light" this means to me that if you pull a coral from ocean and immediatly put it under blue led's (or blue whites) the coral doesn't understand it is recieving plently of light to feed zoox, allows too much chlorophyll production, zoox is overfed, multiply and lead to an incease in in o2 production( increase in ORP) ,increase of biproducts, leads to complete zoox bailout and death. Thats my my very basic understanding anyway, and really is reason for slower aclimation of coral to led light regarless if they came from the ocean, or other artifical "full"spectrum lights....which have NEVER been true "full spectrum" in the first place and is more of a term coined by the industry.

 

[kpiotrowski]

example of a light that could be marketed as "full" spectrum is any light that puts out radiation in the 400 to 700nm range, regardless of were the peaks on the spectrum are. consider the difference in a light that is marketed as full spectrum for growing coral, and one for growing plants. very very simply corals have adapted to use more blue spectrum because the ocean fliters out the high red spectrum, and plants use more of the red. but back to the article and topic.

http://www.advancedaquarist.com/2012/10/aafeature

 

[spieszak]

I haven't gotten to the article yet, lots of things to get done today, but you guys are also a lot more versed in the whole thing than I am, as I'm running T5's on everything but the nem tank, and don't think I'll be switching until I do the 'big' upgrade I have planned... So I just try to keep up with whats going on, rather than be totally versed in it. I just wanted to note here (again) that I only brought it up in the other thread as an awareness thing... and probably only at that because I fell for what seems to be a pretty misleading title. I can't imagine there are folks that would value my opinion on the subject, especially not over all of you, but if someone were silly enough to actually do so, first of all DON'T, that is just silly LOL ... and secondly, I just want to put out there that I am NOT well versed in the subject as it stands. I don't want to in anyway appear as though I have any detailed knowledge on it, or imply that in anyway.
I do hope to get to the article/study this weekend though, because the discussion here seems interesting, and it certainly appears that you all could school me on any questions I might have.

 

[kpiotrowski]

Don't get me wrong either, I am in no way an authourity in this matter as far as being able to spit out all facts where the may lie....but I know enough that after I read the article and started to hear all the red light bashing and fear....and espescially due to the absolutley rediculous title. Well, I think I'm going to have to write a letter to the editor over there at AQ!

Again, I have NO red Led's in my diy...its not that I think it is not ideal, I belieive they they would be ideal and NOT harmfull if it was practical to incorperate them and them be able to have even coverage accross the tank at appropraite spectrums and intensities. for that your typical fixture to have truly full spectrum and over a standard 55g tank would need like 1000 leds, like 50 each of 20 differnt color temps. each color temp having controlable output.

 

[spieszak]

So, having made it through the actual study as opposed to the article, I'd have to say I don't really see anything in there that disagrees with anything that has been posted here. The abstract specifically states

"Overall, our results suggest that red light negatively affects the health, survival, symbiont density and NDVI of S. pistillata, with a dominance of red over blue light for NDVI"

and the discussion notes

"The ecological implication is that red light may be an important sensory cue to detect high irradiance, negatively regulating zooxanthellae density and chlorophyll a synthesis to reduce photodamage and bleaching sensitivity."

To me that says nothing more than an over abundance of red leads to problems, and that further research would need to be done to truly evaluate at what percentage or real time value the red spectrum begins to lead to issues....

The study is also specific noting that

"Although shallow-growing corals are exposed to red light of similar intensity as used in this study [8], it is possible that the genotype used for this experiment was collected at a depth where red light is nearly or completely absent (<10 m) [8], rendering this coral sensitive to excess red light."

and from that we can somewhat extrapolate that the author draws the conclusion that the effect would be much more likely on a deep water species where the natural red spectrum would be filtered out at depth.

I also don't really see much of anything in the findings not in line with previous studies done. To me, the study says that we need to ensure we are tailoring the amount of red light to the corals we intend to keep, rather than "red light is bad", but I am also not in total disagreement with the hyped up title from AA either, since in reality, the title as written does summarize in 10 words or less the findings as posted, at least in my reading. I would be more in agreement with the title if they had noted "an over abundance", but for 10 words or less, its not totally out of line.

What I find most interesting about the entire thing is summed up in this graph though, as what I read from it is that the addition of red is completely unnecessary, at least in the short term.. and if that would prove out over the long term (and on corals other than that specifically used in the study), it would seem to indicate that the addition of red to the spectrum provided would lie closer to risk on any risk/reward scale.

 

[trido]

"the study reinforces the theory that corals use red light as their gauge for light intensity and regulates photosynthesis according to the amount of detected red light" this means to me that if you pull a coral from ocean and immediatly put it under blue led's (or blue whites) the coral doesn't understand it is recieving plently of light to feed zoox, allows too much chlorophyll production, zoox is overfed, multiply and lead to an incease in in o2 production( increase in ORP) ,increase of biproducts, leads to complete zoox bailout and death.

This is exactly what I took from this article. I'm all about SPS.

 

[kpiotrowski]

so now what happens when an led manufactuer puts in a single red led every say 8 inches ( pretty common) in their fixture and powers that led to provide the same or close to same light intentsity as the others. Isn't that coral directly under that red LED getting a higher level of red light as in this study? I know it may seem like I've flipped sides here, but I really have not!

I have never believed that led fixturtes could provide good consistant coverage over a large area with the puck design. ive seen the crazy high par on a meter 12 inches below drop off very quickly every inch you move to the side. but in a puck design I would think that that one or two red led's would have less of a negative and more of a natural spectrum of say metal halides as it basically incorperated into the light "beam" these pucks produce. However I have seen some VERY nice sps tanks growing great with the puck design like radions, so the fact that they have very uneven par across the tank must mean very little in the real-world of this hobby is all I can conclude.

For me when it comes to led fixtures I would have to belive in results in the real-world, and just go with what others are having success with.

 

[sryder]

Don't forget that when their is a red every so often in a fixture you get that really crazy disco ball effect..lol