deep red led question

[saltwaterpicaso]

i got my leds in for my full spectrum build within the build im copying there are 2 deep red leds. someone mentioned i should replace the red with green becouse the red will grow algae. i know all light grows the stuff but will the red really make it as bad as he said it would. any input would help. the build is 20 rb, 4 b, 8 nw, 8 uv, 4 cyan and 4 deep red.

 

[blanden.adam]

I don't think so. Red does allow algae to grow a bit better, but it also is within the spectrum of the zooxanthelle of your corals, and helps your reds pop a bit more. A thing people often forget about our corals is that the zooxanthelle that let them derive energy from light are actually endosymbiotic dinoflaggelates, one of the nastiest algae's around to deal with! So, if your light will grow coral, it will also grow some species of algae, albeit to a different degree.

If we look at what commercial ficture manufacturers are doing, Ecotech has deep red in their fixtures, 4 of them per fixture run at 3W each (34 LED's total), which is way more than most people include in their DIY fixtures, and I have heard nothing but excellent things about them. Vividaquariums and Mr. Saltwater Tank use the echotech fixtures over their display tanks, and they look awesome.

Therefore, IMO, the deep reds will help your tank look better and your corals grow a bit better, and as long as you control nutrients and have a decent cleanup crew algae won't be a problem. I will also be including a deep red LED in my LED fixtures for my next tank, if that's worth anything to ya.

 

[teamdulski]

Call me old fashioned, but red disappears naturally at ~20 feet deep. So what use do corals really have for it since most are collected from depths deeper than that? If someone has a scientifically backed answer please let me know as I have been searching for one.

 

[blanden.adam]

The Chlorophyll molecules used by the symbiotic zooxanthelle to absorb light (primarily chlorophyll a), which are shared by all algae and even higher plants, have 2 primary absorption peaks where they absorb the most light. One is in the 420-470 nm range (blue) and the other is in the 650-680 nm range (red). There are also many accessory pigments used by the zooxanthelle for photosynthesis (e.g. caratenoids) that allow the absorption of nearly the entire range of visible light, as well as non-photosynthetic pigments used for things like protection form UV radiation that give our corals their outstanding fluorescent colors.

Although as you get deeper in the ocean there is less and less red light, the molecules used to absorb the blue light, which penetrates deeply, are the same that absorb the red. We can take advantage of that in our aquariums with deep red LEDs -- even though it might not have gotten much red light, they can still use it. And the red LEDs also allow us to see the reds in the corals that our typically blue-dominant lighting systems wash out, which is just pretty

 

[teamdulski]

Do you have a link to this?

 

[blanden.adam]

It's compiled information, but a google search will give you the absorbance spectra of any of the pigments you want in at least 1 solvent. For Chlorophyll a and chlorophyll b, these spectra are pretty good: http://www.biologie.uni-hamburg.de/b-online/e24/3.htm.

For a different spectrum of chlorophyll a taken in methanol and with easier to find experimental details, you can see the PhotochemCAD database, or just go to this website: http://omlc.ogi.edu/spectra/PhotochemCAD/html/122.html.

Although old, a paper titled "Photosynthetic Pigments of Symbiotic Dinoflagellates (zooxanthellae) from Corals and Clams" by Jeffery and Haxo presents a chromatography study that should give you an idea of some of the pigments found in symbiotic dinoflagellates and their absorbance maxima in some different solvents (http://www.biolbull.org/content/135/1/149.abstract, click on Full Text PDF to get access to the full article).

 

[SkiFletch]

Interesting paper Adam. We have/had a member here by the name of Chris (we have enough of those ) who used to work at ARC whom took courses from a professor in college who was studying just this. His professor's work was mostly with Atlantic species, but he found that corals he and his students collected from various depths, and various species had concentrations of different types of zooxanthellae. Chris told me it was a common older misconception that all corals harbored the same zooxanthellae. He said relatively recent research has shown that there are different "clades" of zooxanthellae, each with different genetic compositions. Each Clade has different light responses to different wavelengths, power of light, and of most interest to the researchers heat resistance to protect against bleaching events.

Not sure if this article is based on the same research as Chris' professor, but it is "newish" and describes it in WAY MORE detail than I have time for

http://www.advancedaquarist.com/2006/1/aafeature1

Long story short, not all corals have zooxanthellae that use red light, but all corals have zooxanthellae that use blue light. MANY types of nuisance algae have cholorophylls that excel at using red light. As mentioned by another poster, MANY corals live below 30' of seawater where red light does not reach. They do just fine...

 

[blanden.adam]

Very interesting. I've actually read that article in the advanced aquarist before. I'm not surprised that there are clades of zooxanthellae, or even variations within a species of zooxanthellae have different responses to light.

I would be very interested to read the papers demonstrating the different light responses though! Because if there is no response to red, that would also imply that there are very low or non-existant levels of chlorophylls A (and B), which would surprise me indeed! This would also be surprising because, as you say, all zooxanthellae use blue light, which is predominantly accomplished by chlorophylls, and those molecules are the same that absorb red. If they absorb blue and not red, this would mean that there is another chlorophyll-like pigment absorbing the blue light that I don't know about, which would be sweet.

Any idea where we can find this information?

 

[SkiFletch]

They said more that there were varying responses, not NO response. Sadly I havent seen Chris around in a while to ask him. Maybe Randy knows where he shuffled off to furthering his studies.

 

[zooman72]

I have a couple of deep reds (~660nm) in use over my 29g gorgonian tank, and I cannot grow algae in that tank if I wanted to - excess nutrients play a greater role with nuisance algae. One must remember that the reds are primarily for color rendition, and really not a photosynthetic driver as the various blues are. However, I am sure that there are a lot of shallow-water corals that do receive some red light in nature - they are not all at 30 feet and below.

SWP is also probably using the reds in combination with the cyans and blues ("cool blues") for color rendition, and if they are grouped together closely will emit a mix of white light - alot of other aquarists (and manufacturers) are doing the same thing, and they are not doing it to improve PAR (or PUR), but to improve the "look" of the tank and corals, allowing certain colors to "pop" that would otherwise wash out under blues and whites. Please note though - make sure to use quality nuetral whites (~5000K), and with the cyans and nuetral whites there is really no reason to use green.

 

[saltwaterpicaso]

http://i1230.photobucket.com/albums/ee490/saltwaterpicaso/089-1.jpg

 

[saltwaterpicaso]

 

[saltwaterpicaso]

this is going to be my clustering. there will be 4 clusters in this orientation im hoping this will be enough leds for a 72 gallon bowfront reef if not there will be enough room on the heat sink for more leds the heat sinks are 6*20 im not sure how many leds can go on each heat sink

 

[zooman72]

# of LEDs depends on whether optics will be used and how efficient the LEDs are - Cree and Luxeon are much more efficient and luminous than cheaper LEDs (such as Bridgelux) run at the same current, so you need fewer of them.

# of LEDs on a heatsink depends on the heatsink itself (mass and surface area of the fins for example) and whether you are actively cooling it or not. If you do not have an infrared thermometer, get one, as it will tell you what temp the LEDs and heatsink are reaching.

The clusters look good, but why are you running the RB's and whites at 1300ma's? Remember, peak efficiency is not always reached with peak power, and running certain LEDs flat-out may shorten their life and increase the need for active cooling. If they are one of the "latest and greatest" Cree's however, they may be OK...good luck and keep us posted!

 

[saltwaterpicaso]

i dont know why there are going to be run at 1300ma im actually copying a light off from youtube that i really liked. any input would help at what to run them at. the leds im using are all cree bought from rapid. ive already made a light with bridgelux and want to see the differences. oh and the white leds are 5w according to rapid

 

[saltwaterpicaso]

all channels with be run at 80% except the whites will be at 60%

 

[zooman72]

OK, if the whites are the XP-G's, then you could run them that high, but it will cut into the lifespan - 1000ma's is probably enough. If the royal blues are the XT-E's, the same goes, probably don't need to run them at more than 1000ma's.

Also, no need to map out what percentage to run each channel until you see them in operation, and then you can tweak them to your desired levels...

 

[saltwaterpicaso]

i was going to go with rapids pwm but now im going to go with the typhoon controller has anyone on here used one or know anyone that has. it says it can be reprogramed i wonder if it can do cloud coverage and yes the leds are xpg and xte

 

[saltwaterpicaso]

if you dont recomend 1000ma then what should i run those 2 drivers at

 

[zooman72]

Sorry, I have never used the Typhoon controller, but I have read lots of very good reviews on them.

Also, I am sorry for the misunderstanding, but I do believe that running the drivers for those 2 channels at 1000ma would be OK. If you really wanted to pump up the output of the emitters you could also safely run them at 1300ma, it's just that running them higher does have it pros and cons. I cannot recall what size tank you are running them over either, and you may not need to run them that high.