best spectrum for reef tank

[TbyZ]

Thinking about a diy led light for a reef tank.

Has the best spectrum been decided on?

UV, what nm range?

Blues, what ranges

white, what kelvins?

Purple/violet?

660nm ?

and what about ratios

thanks for any feedback

 

[Waters]

Sorry I don't have the expertise to answer your questions but maybe look at some of the higher end LED models and duplicate what they are using?

 

[Dana Riddle]

There is no spectrum that will best meet the requirements of all photosynthetic organisms. The spectral needs of a red alga is different than that of a green one. Zooxanthellae have the photopigment peridinin that absorb at least part of the green spectrum that green plants do not use as effectively. The best we can do is meet general lighting requirements. So, if designing a DIY LED panel, include blue, green, white, and a red one (or two.)

 

[TbyZ]

There is no spectrum that will best meet the requirements of all photosynthetic organisms. The spectral needs of a red alga is different than that of a green one. Zooxanthellae have the photopigment peridinin that absorb at least part of the green spectrum that green plants do not use as effectively. The best we can do is meet general lighting requirements. So, if designing a DIY LED panel, include blue, green, white, and a red one (or two.)

Dana; thanks for your reply. How important is the wavelength below 410 nm, in your opinion?

 

[Dana Riddle]

410 nm is moving away from the absorption peaks of protective pigments (diadinoxanthin & diatoxanthin) so naturally these wavelengths have a better chance in being used in photochemistry. If we look at the absorption curves of chlorophylls a and c2 (found within zooxanthellate), we see shortwave ultraviolet radiation can be used in photosynthesis. Protective pigments (Mycosporine-like amino acids, or MAAs) don't provide any protection against UV until around 350nm and below. There's a good reason for this - some UV wavelengths are used in photochemistry, so some of the UV LEDs provide more than the 'pop' (I hate that term) to coral fluorescence.

 

[TbyZ]

410 nm is moving away from the absorption peaks of protective pigments (diadinoxanthin & diatoxanthin) so naturally these wavelengths have a better chance in being used in photochemistry. If we look at the absorption curves of chlorophylls a and c2 (found within zooxanthellate), we see shortwave ultraviolet radiation can be used in photosynthesis. Protective pigments (Mycosporine-like amino acids, or MAAs) don't provide any protection against UV until around 350nm and below. There's a good reason for this - some UV wavelengths are used in photochemistry, so some of the UV LEDs provide more than the 'pop' (I hate that term) to coral fluorescence.

so, looking at this graph, there would be no point really in going below 400 nm

 

[Dana Riddle]

You need better charts . The Queen of Chlorophyll (Shirley Jeffrey) has charts showing absorbance down to 350 nm.

 

[TbyZ]

You need better charts . The Queen of Chlorophyll (Shirley Jeffrey) has charts showing absorbance down to 350 nm.

(Can you show her graphs if possible please? )

Ok, so what % of light in that spectrum range should be standard?

 

[TbyZ]

I found this very good article http://www.advancedaquarist.com/2014/5/aafeature

so Chlorophyll a peaks at 382.7 nm & Chlorophyll c² peaks at 395.5 nm

very helpful

 

[Dana Riddle]

I found this very good article http://www.advancedaquarist.com/2014/5/aafeature

so Chlorophyll a peaks at 382.7 nm & Chlorophyll c² peaks at 395.5 nm

very helpful

Thank you! I hope to get back writing similar articles soon. Preparations for the move from Hawaii, actually moving, and now getting unpacked and the new lab built/set up has taken a year away from me.

 

[Dana Riddle]

Here you go. Quality not the best, but you should get the gist of it.

 

[MacD]

Just curious, but what would you think about an led spectrum like this one?

 

[kevensquint]

IMO your tank will look very white/bright and you may get excessive algae. There is no need for an equal amount of yellow, orange,red with regards to blues. Theses days people keep the proven high blue and fiddle with adding touches of the green, yellows, reds etc. If you start with that spectrum you will likely End up going back to the standard bluer spectrum later on .

 

[MacD]

Hello and thank you KevenSquint. I'm dabbling in the realm of full spectrum LEDs and was considering the spectrum above since it has ample amounts of all colors. Algae would definitely love this light, so I would have to plan for that accordingly. Thank you! = )

 

[kevensquint]

It should perform like a 6500k bulb. So similar look to shallow water diving. Very bright yellow tint....

 

[MacD]

Just a random thought...but do you think this light would grow coral, provided there's enough LED bulbs put together to generate 250-350 PAR? I ask because the amount of color included in the spectrum looks promising for zooxanthellae photosynthesis. I also think that putting enough of these together would mimic the light/intensity of a metal halide.

 

[jda]

All of the charts and stuff aside, you also need a bulb that looks good - you could make a 5500K bulb that grows stuff awesome, but you would not likely be happy with it. Nearly every LED manufacturer tries to duplicate the spectrum on a 20K Radium. That is a good place to start. If you can actually do it, then you can build them and make a fortune - everybody else's attempts are middling at best, IMO. While 20K Radium is not perfect for every organism, it does have nice output from 350 to over 700 and most of what is kept in captivity can thrive under it. If you want it whiter, then look at the spectrum from 10K XM or 10K Hamilton and blend these between the 20K Radium.

 

[kevensquint]

It's both as simple as that as well as much more complicated than that. Eric Bourneman once said " I can grow coral in a tank on a windowsill, but that doesn't mean it's the best option". ( paraphrasing).
That PAR with a full spectrum light will grow corals, tree's, algae, cyano etc... But with regards to optimal growth and coloration we normally want to see in our tanks, it's not likely going to be the best all around spectrum for that. 6500k MH was yellowish and popular 15-20 years ago. It did grow corals, but looked like someone pee'd in the tank and corals looked yellow, green and brown. So yes your spectrum can work, however it's like taking a step back in time unless you are curious it's always fun to see things for ourselves.

 

[MacD]

Thank you JDA and KevinSquint. Really appreciate the assistance, explanations and examples. I've been trying to wrap my head around spectrums for a while and while very curious to see what would be the outcome trying different things, I would rather have a reef tank that grows and looks great, rather than one that grows...but looking terrible. Thank you!

 

[kevensquint]

Google images, 6500k iwasaki ( it's an old MH bulb) =