Are all acros loving led? Are coral enduring less par from led than T5/halides?

[Dennis Cartier]

430 seems an odd choice, considering the absorption curve of the blue spectrum.

Not really. 430nm is pretty close to the best absorption across the entire spectrum. Dana provides some data on the absorption in his article below.

Photosynthetic Efficiencies of LEDs: Results of Short Term Exposure to LED Lights

Dana Riddle studies zooxanthallae exposed to varying intensities and colors of LEDs between 365nm (UV-A) and 657nm (red). The collected data sheds light on how different spectra affect photosynthesis and the Xanthophyll Cycle, helping us to better understand how corals use and respond to light.

reefs.com

My interest in 430nm came about when I built my own DIY LED lights back in the day. The offerings were still the blue and white basic lights back then. I built some huge aluminum plates covered in LEDs with a bunch of spectrum ranges accounted for. I could only get the 420nm and 430nm LEDs in 20W COB modules. What I noticed was that my corals tended to grow towards where the 430nm modules were in the fixtures above them. That got my attention.

 

[Nonya]

Not really. 430nm is pretty close to the best absorption across the entire spectrum. Dana provides some data on the absorption in his article below.

Photosynthetic Efficiencies of LEDs: Results of Short Term Exposure to LED Lights

Dana Riddle studies zooxanthallae exposed to varying intensities and colors of LEDs between 365nm (UV-A) and 657nm (red). The collected data sheds light on how different spectra affect photosynthesis and the Xanthophyll Cycle, helping us to better understand how corals use and respond to light.

reefs.com

My interest in 430nm came about when I built my own DIY LED lights back in the day. The offerings were still the blue and white basic lights back then. I built some huge aluminum plates covered in LEDs with a bunch of spectrum ranges accounted for. I could only get the 420nm and 430nm LEDs in 20W COB modules. What I noticed was that my corals tended to grow towards where the 430nm modules were in the fixtures above them. That got my attention.

Very interesting read. This one made me wonder why my DIY LEDs way back when were so good at promoting coral growth: "Results of these experiments suggest that violet, blue, and red light with peaks away from the absorption maxima of carotenoids present in zooxanthellae are most efficient in the promotion of photosynthesis...LEDs with peaks of 400 and 420nm were more efficient than those with peaks at ~450 and ~480nm. The combination of LEDs producing red light (at 631nm and 657nm) was most efficient with practically none of its output absorbed by carotenoids."

Dana's experiments with monochromatic LEDs years back showed that red light bleaches corals. I saw another study in which significant amounts of red light could negate the photosynthetic effects of blue light.

 

[Nonya]

So my question is, Why do the two blue absorption peaks exist, when the exposure to blue wavelengths from sunlight doesn't have similar peaks?

 

[Nonya]

One possible explanation is in the title, "Results of Short Term Exposure to LED Lights". Would the results of long-term exposure be completely different, as in shifted toward 450 and 470nm?

 

[Superlightman]

Not really. 430nm is pretty close to the best absorption across the entire spectrum. Dana provides some data on the absorption in his article below.

Photosynthetic Efficiencies of LEDs: Results of Short Term Exposure to LED Lights

Dana Riddle studies zooxanthallae exposed to varying intensities and colors of LEDs between 365nm (UV-A) and 657nm (red). The collected data sheds light on how different spectra affect photosynthesis and the Xanthophyll Cycle, helping us to better understand how corals use and respond to light.

reefs.com

My interest in 430nm came about when I built my own DIY LED lights back in the day. The offerings were still the blue and white basic lights back then. I built some huge aluminum plates covered in LEDs with a bunch of spectrum ranges accounted for. I could only get the 420nm and 430nm LEDs in 20W COB modules. What I noticed was that my corals tended to grow towards where the 430nm modules were in the fixtures above them. That got my attention.

I think that is a good point, if you look the t5 tubes they all have a spike in the 430 nm and we now their good results. Also I check wich led have the most user satisfied and the tanks of my friends with the best results and they are probably the reefi and the kessil and guess what, they are the two with the most 430 spectrum. I think we hold something here.

 

[Superlightman]

Also the difference between the t5 and the leds when you look a spectrometer and not only a picture, you will see that the spectrum of t5 not move whereas the spectrum of led in the tanke move he not stay same as it is a superposition of the different led, each one forming a cone.
I think also led with one led with all different colors same as the kessil may be the best as all come from a single cell, the spectrum is much more stable than classic led or led bars, even if the spread is less good.

 

[Midrats]

Just out of curiosity,you keep a reef tank correct ? I just always see you in the lighting forum and have never seen a tank thread.

Why does that matter?

 

[Steven Garland]

Why does that matter?

Simple question,if you read my whole post you would see the reason I asked. Fairly common question if you ask me.

 

[Bpb]

Why does that matter?

I tend to agree. If he made bold recommendations left and right and tried diagnosing coral health issues that would be one thing. But his content is 99% informative and unbiased on the physics of light production. Never understood why people got so upset about him not being a reefer. I find his posts highly educational. People get worked up when he presents information which might shed light on misinformation, no pun intended. There are a good many reefers who know far less about lighting, and many whom have never sniffed any success themselves who like to point fingers. This is not a pointed post. Just saying. I agree with the “why does it matter” comment

 

[Nonya]

I think that is a good point, if you look the t5 tubes they all have a spike in the 430 nm and we now their good results. Also I check wich led have the most user satisfied and the tanks of my friends with the best results and they are probably the reefi and the kessil and guess what, they are the two with the most 430 spectrum. I think we hold something here.

Too anecdotal for me. The action spectrum maximum encompasses most of the violet-blue range. I had sudden, massive growth with blue, royal blue, and dimmed white LEDs long ago. There could be other factors at play--the presence of too much red, overall PPFD parameters, chemistry of each tank, flow, even the age of each tank, etc. Other than their use for causing certain pigments to fluoresce, are most 420-430nm LEDs too dim to be worth taking up real estate in a luminaire?

 

[Steven Garland]

I tend to agree. If he made bold recommendations left and right and tried diagnosing coral health issues that would be one thing. But his content is 99% informative and unbiased on the physics of light production. Never understood why people got so upset about him not being a reefer. I find his posts highly educational. People get worked up when he presents information which might shed light on misinformation, no pun intended. There are a good many reefers who know far less about lighting, and many whom have never sniffed any success themselves who like to point fingers. This is not a pointed post. Just saying. I agree with the “why does it matter” comment

I never once got upset,nor care if he has a tank. I asked a serious question because I was actually curious and never asked before until I did in my post. There was no underlying shade being throw his way whatsoever.

I have found TONS of his info valuable before,and even taken some into consideration when building my own lights.

 

[Bpb]

I never once got upset,nor care if he has a tank. I asked a serious question because I was actually curious and never asked before until I did in my post. There was no underlying shade being throw his way whatsoever.

I have found TONS of his info valuable before,and even taken some into consideration when building my own lights.

That’s fair. I tried to be pretty clear that was not a pointed post directed at anyone. Lots of people have brought this topic up. Wasn’t directed toward you in particular. Just convenient timing for me to add my $0.02

 

[Nonya]

Maybe we can end the controversy once and for all and crowd fund his first SW tank? I think he said he has (yuck) FW.

 

[Superlightman]

Too anecdotal for me. The action spectrum maximum encompasses most of the violet-blue range. I had sudden, massive growth with blue, royal blue, and dimmed white LEDs long ago. There could be other factors at play--the presence of too much red, overall PPFD parameters, chemistry of each tank, flow, even the age of each tank, etc. Other than their use for causing certain pigments to fluoresce, are most 420-430nm LEDs too dim to be worth taking up real estate in a luminaire?

I think it is important to put them, even if you are not seen them, if your coral health improve. Check the wave length the corals absorb, and you will see it is one of the most important spectrum. This debate was the same with the actinic tubes.If I follow your idea, then the manufacturer should put only what is nice to our eyes and which would result in very poor results.