Spectral Distributions of LEDs

[Sahin]

I've been waiting for this a long time. Here you are: Feature Article: Spectral Distributions of LEDs: AI-Sol, Radion, Orphek, EcoRay, Mvava — Advanced Aquarist | Aquarist Magazine and Blog

 

[CalmSeasQuest]

Many of us have been waiting for Sanjay to complete this Now the question is supplement red, UV or both.

 

[Howard@Maxspect]

What you really need, imho, is 410-420nm, that's utilized by Chlorophyll A for photosynthesis (peak absorption at 412nm):

You'll find 410nm/420nm in MH/T5 spectrum but you rarely find it in any LED fixtures.

p.s. source: Chemical Education Journal(CEJ), Vol.13, No.2/Registration No.13-22

 

[Sahin]

I agree that additional LEDs in the 410-420nm range would be very useful for coral growth. But I feel that the addition of red LEDs for those commercial units that don't have them is also useful aesthetically at least.

 

[CJO]

I didn't see anywhere in the article whether he was using glass shields with the MH lights. The glass shields are commonly used to filter out the UV light.

CJ

 

[ReefLEDLights]

I've experienced outstanding growth using the Royal Blue 450nm LED. That said Bins of Cree LEDs matter. The Royal Blue has a range of 450-465nm the 450 gives a better colour pop. The Cree Cool White LEDs have a range of 5-8K depending on which bin you choose you can have more or less yellow.

Using UV, Reds or Green is great to tweak the colour to get the perfect look.

Bill

 

[TheEngineer]

I've yet to be all that impressed with the output of the UV leds. I've been supplementing my LEDs with T12 actinics and have loved the colors. Until LEDs can match that, I think I'll stick with them.

 

[ReefLEDLights]

I've yet to be all that impressed with the output of the UV leds. I've been supplementing my LEDs with T12 actinics and have loved the colors. Until LEDs can match that, I think I'll stick with them.

We've tested the 410UV against the XT-E Royal Blue and to the naked eye the coral colour pop was about the same. Sadly the ccd in our Nikon Camera was unable to document this without serious Photoshop and then that would invalidate the comparison. The big difference was intensity the XT-E were much brighter.

That said UV may have a long term effect on certain pigments which may enhance the coral colour. Given your budget they may be a worthwhile addition.

Bill

 

[Big E]

I didn't see anywhere in the article whether he was using glass shields with the MH lights. The glass shields are commonly used to filter out the UV light.

CJ

The mogul bulbs don't need UV shields.............. the actual bulb is the UV sheild. The MH bulbs used for the test are 400w mogul bulbs.

 

[CJO]

The mogul bulbs don't need UV shields.............. the actual bulb is the UV sheild. The MH bulbs used for the test are 400w mogul bulbs.

Thanks for the info!

CJ

 

[mcarroll]

Very interesting!

In related browsing, I found this really short, really awesome primer on EM radiation as it pertains to our thread of the moment. (Part of a course syllabus I think...so if you're really interested, keep readin! )

Here's a choice quote to get you to click and read more:

If you write out wavelengths from 700 nm to400 nm in steps of 50 nm (that is, write out the list 700 nm – 650 nm – 600 nm – 550 nm –etc.), and then arrange the letters ROYGBIV above the numbers spaced out evenly above them with yellow and green to either side of 550 nm (the middle of the region), then you will have the approximate wavelengths of the various colors, as shown...

Also, just for reference (FWIW since they were a main point of reference in the article), Radium publishes their official spectral info on their bulb pages (e.g.):

165w (aka 150w HQI)

...interesting that it looks like they've changed formulation on these....wonder when? I know the ones in my fixture now don't look any different than they ever looked, but who knows how long local USA stock would take to rotate and see new stock from Germany? (There's no other DE "colored" bulb listed at this wattage, either.) Hrm.

Here's my local copy (don't ask) of their spectrum graph from their site from sometime around 9/2009:
(and IIRC they characterized it as a 170w bulb back then....150w nominal. I know I pulled 179w at each ballast when running them when I measured back then.)
150w HQI(2009)

Anyway, the bigger bulbs seem consistent with the past:
270w (aka 250w)

360w (aka 400w)

Finally, just for perspective, is Radium's curve of sunlight:

Wish it was more common for makers to publish this info (some do)....one more small reason to love Radiums if you're running halide.

To my eye, judging from their curves, the bigger bulbs (i.e. with traditional Radium color) spike in the lower-reds (nearing orange) rather than the spiking somewhere in the "full" reds - around 675nm from TFA. (That spike looked like around 685nm in Sanjay's old bulb analysis on manhattan reef's site...as always, YMMV I guess. ) The lower reds aren't too hard to come by in LED....I plan to add a few 620-625nm red GU10's (like this) to my collection for testing. I guess I'll see if they do anything (positive or negative) to the look I've got going now (26 daylight/4 blue). Maybe something around 650nm or 675nm will become available by the time I (and the budget) get around to it.

-Matt