LED Spectrum Peaks - is it possible to speculate?

[Dana Riddle]

Also, Seneye has a meter that reads PAR and approximate PUR for home reef use.

I ordered the$9 spec. The other two are sold out unfortunately.

 

[Spare time]

The reason we run blue heavy tanks with LED is because we have the ability to do so. With discrete channels to adjust running 450nm many reefers like the pop that 450nm provides. That was tricky to do back in the halide and tube days. Now you can just turn up the blues with a dial or an on your phone.

This has been beaten to death, but theres no evidence 400-440nm violets do anything better than the common 450nm band that is universal to all types of reef lights including LED , halide and T5. Some of the most legendary halide bulbs made for reefing have trivial amounts of 400-440nm but they've grown spectacular SPS tanks over the years. Anybody can write articles on in vitro chlorophyll absorption ratios but ask them to show show their side by side SPS tanks and how the one with violet is growing better and they shut up because it doesn't exist.

Don't buy into the violet nonsense. Most of the mainstream lights have them anyways. Base your choice on features and coverage.

Color does play a big role. Certain wavelengths are much more readily used in photosynthesis than others. Yes one obviously doesn't need violet, but its color that can fuel better production in the zooxanthellae than if you did not have it.

 

[spideybry]

For those who want to see coral non-fluorescent as well as fluorescent pigments, the general rule of thumb with LED arrays is make sure you have sufficient 'actinic' for photosynthesis...and then tweak the white/other colors to your viewing preference. For those interested in just the 'black-light poster' look, a very strong actinic with minimal white/other colors works, too.

I've been experimenting with a touch less 'white' and more 'cyan' than I typically run lately and the corals/false corals are most fine with it

This is the spectrum graph from the DIY spectrometer program:

Small 12g tank, so I was running a bunch of Stunner Strips in addition to DIY LED strips at the time. Gives you an idea of the output format.

Just in case you weren't aware, there is an 'Aquarium Lighting Forum' here on R2R (run by Dana Riddle) with lots of great info:

https://www.reef2reef.com/forums/aquarium-lighting-by-dana-riddle.956/

Really appreciate this info - I can't wait to try to figure out the spectrum of this light. Also the tank looks happy and healthy. Surprisingly clean

Also, Seneye has a meter that reads PAR and approximate PUR for home reef use.

Honestly, had I known this meter existed I would have picked it up. For the price, you can't beat that. I just wonder how accurate it is. Though even if it is just in the ballpark, I think I can be happy with it. Definitely picking one of those up.

Post PAR numbers when you get a chance. Need to know model # (MQ-510, etc.), sensor color (blue or white) and if measurements were in air or water.

I have this thread (linked below) going on right now in the Lighting Forum that has some info on the light that I am working on specifically. Any input would be greatly appreciated considering I only have one more day with the PAR meter.

The meter I am using is an Apogee MQ-510 with a white sensor.

https://www.reef2reef.com/threads/p...ne-have-input-suggestions.752722/post-7931922

 

[Dana Riddle]

Color does play a big role. Certain wavelengths are much more readily used in photosynthesis than others. Yes one obviously doesn't need violet, but its color that can fuel better production in the zooxanthellae than if you did not have it.

Can you clarify why violet isn't needed? Just curious.

 

[Spare time]

Can you clarify why violet isn't needed? Just curious.

My apologies, I worded that poorly.
I wanted to edit that but sometimes I can't edit one of my messages andI am not sure why?

But I was trying to get across that the coral can probably "survive" with a limited violet spectrum (I meant to say a tiny but not 0) but that its probably gonna be more beneficial to have the purple and violet and not just blue at 450nm. More of one of those where they could thrive or just survive (reference when brs did a light master video where they noted that very narrow spectrums can probably keep coral alive but not keep them thriving). Thank you for replying so that I can better clarify what I meant!

 

[Spare time]

My apologies, I worded that poorly.
I wanted to edit that but sometimes I can't edit one of my messages andI am not sure why?

But I was trying to get across that the coral can probably "survive" with a limited violet spectrum (I meant to say a tiny but not 0) but that its probably gonna be more beneficial to have the purple and violet and not just blue at 450nm. More of one of those where they could thrive or just survive (reference when brs did a light master video where they noted that very narrow spectrums can probably keep coral alive but not keep them thriving). Thank you for replying so that I can better clarify what I meant!

I also think I should clarify I am calling violet 400nm ish area with blue starting somewhere around 420nm or 430nm.

 

[phys]

Long ago i designed my own spectra based off those graphs of photosynthetic corala, the graphs of the LED outputs, and the relative intensity of each LED combo.

Recently i took a spectra of it since i was borrowing a spectral analyser for other work i was doing... It was pretty spot on for what i wanted.

 

[Spare time]

Long ago i designed my own spectra based off those graphs of photosynthetic corala, the graphs of the LED outputs, and the relative intensity of each LED combo.

Recently i took a spectra of it since i was borrowing a spectral analyser for other work i was doing... It was pretty spot on for what i wanted.

Any clue of a place that rents those?

 

[MabuyaQ]

Have you seen this article by @Dana Riddle? There might be an inexpensive way to evaluate your hypothesis of PAR value estimates.

The OP question is about PUR (combination of PAR and spectrum) this article shows how you can make a diy PARmeter so spectrum remains unknown. You can blast corals with high intensity low PUR spectrum to get/measure the same PAR as you would get with high PUR spectrum at lower intensity.
The highest PUR light for chlorophyll a for photosystem 2 is 680nm (red) and for photosystem 1 it is 700nm (red) as that is what drives the creation of free electrons in the primary photoreaction site. And the sum of 680+700 is even greater than the sum of its parts. All other wavelengths rely on the transport of electrons to these primary photoreaction site and like with any other transport system there is a loss of efficiency involved. You could basically run a tank on just 680nm and 700nm LEDs, but he corals would look white/bleached and with to much light (intensity or duration) they would 'burn' and die. It is the blue spectral peak in the chlorophyll a spectrum that controls this 'burning' mechanism as it reacts to the amount of light received at this peak (which in nature is directly related to the amount of red light received).

 

[phys]

Any clue of a place that rents those?

I doubt anywhere rents these. These are used primarily for scientific lighting research and industrial lighting analysis. They're availble for public purchase but cost a few grand since theyre a self contained spectragraph and intensity meter. The model number is in the pic if anyone wants to look them up. There are "cheaper" things that emulate this but cheaper is still around 500$.

 

[Dennis Cartier]

Concerning the spectra of LEDs used. I would much rather have more 430nm LEDs and less 450nm LEDs in a fixture. However 430nm is a spectrum that is rarely ever seen in most LED fixtures. I used some 20W COB 430nm LEDs in my first DIY fixture in the past and the corals seemed to prefer it. They grew towards the 430nm LEDs.

While I am at it, if only chlorophyll A and C are used by Zooxanthellae, why do so many vendors still show it as being photo synthetically useful in a reef tank? I am looking at you Orphik. Or are they showing the plot for chlorophyll C and labeling B in error?

Dennis