Proper spectrum?

[Walla2GSP]

So I've been doing a lot of research on proper lighting since my tank crash two years ago and was getting ready to try my hand at building an LED display for the 35 gallon. All the research I had done said to avoid light spectrums above 600nm as they would encourage algae growth and at times could be detrimental to coral growth. This idea was backed up by my experience as a wreck diver because the red spectrum disappears after only a few feet. So when I planned my display I picked 3W LEDS in spectrums from 360nm to 550nm and daylights at 10K and 20K, with 50% of the stars being 440nm and 450nm Blue.

SO my question is in the last two weeks I have seen a number of hobbyists talking about using LEDs in the 650-750nm spectrum to get better growth rate on their corals. Have I been thinking about this wrong, or are they just growing shallow water SPS that need more red light? I just want to build a display that will give me the best light spectrum for good coral growth.

 

[2smokes]

10 000K has a lot of red in it.If you have white leds i dont think there is a need to add reds (650 nm).Red will help cyano and GHA to grow better in the diplay.And for the shallow water corals like most acropora you could use a perfect spectrum made of all the colors but if its led then you will miss the UV spectrum almost entirely because leds cant make UV light (UVB ,UVC and UVA).For a led lamp i would use mostly royal blue leds as the main source of light and i would add a few ,verry rare red ,blue and green leds.I wouldnt use white leds at all.Green light is useless for corals but its good if you have a yellow fish ,it will make yellow to look yellow not dirt green .

 

[75mixedreef]

Colors fluoresce differently under different color lights. In the reef keeping hobby we drift pretty far into the blue spectrum and sometimes go so far as to lose some of the pop that we might see with other colors present. People add a splash of red to bring things back into balance.

I prefer more of a full spectrum look, but some people want to see the color spikes of red, green, UV, and a large one at blue. That way they can see all the colors present in their tank without anything getting washed out, and they should have a limited spectrum for algae growth. I do have LED's that I will be installing in my upgrade, but I am adding T5s to soften it up a little.

 

[Ron Reefman]

Walla, I don't know who or where you saw that adding red spectrum was a good thing or not. In a reef tank, a little red goes a long way. There is some zooxanthellae in our coral that use red for photosynthesis, and corals do use it for production of pigments and other required internal chemistry. I have 6 channel control and over my reef I run zero red or green and 40% white 90% blues and violet. The corals get enough red spectrum from the white leds. Over my refugium I run 100% red, white, green and 40% blues and violet. Macro algae and plants use more red spectrum to do photosynthesis.

 

[Walla2GSP]

... I have 6 channel control and over my reef I run zero red or green and 40% white 90% blues and violet. The corals get enough red spectrum from the white leds. Over my refugium I run 100% red, white, green and 40% blues and violet. Macro algae and plants use more red spectrum to do photosynthesis.

Thank you Reefman, this was kinda where my mind was with adding the white lights to my display to get all the needed red light. My next project was an LED for the refugium, and I was planning warm whites and reds to give me the best plant growth as I already use them for house plants to get better growth and it's a proven method. Just wanted to make sure I wasn't missing something with corals.

 

[Walla2GSP]

.. if its led then you will miss the UV spectrum almost entirely because leds cant make UV light (UVB ,UVC and UVA)....

Are you sure about that statement?

https://www.thorlabs.com/drawings/9...6-0103-798BF6931AB4EF24/LED325W-SpecSheet.pdf

 

[schnebbles]

Reefman - what light is that on the left?

 

[2smokes]

Are you sure about that statement?

https://www.thorlabs.com/drawings/9...6-0103-798BF6931AB4EF24/LED325W-SpecSheet.pdf

I am right in my statement.Did you see how much a led like that you have posted costs?One led like that costs more than the entire lamp and it only lasts like 1000 hours(not more than an old incandescent bulb).Nobody uses thoose in the hobby,not even the most expensive brand led lamp would not have thoose.The led you posted is indeed an UVB and is made of glass and metal to be able to withstand UVB aggresion for 1000 hours .Normal leds that you see in the hobby are made of plastic and they have 0 UVA,UVB and UVC.If you want full spectrum with UV included then go for MH and T5.Led light sold as UV leds(excepting thoose metal and glass ones) are just pink color not at all UV.

 

[Walla2GSP]

The above is a purpose built LED for lab purposes, but there are low-level UV LEDs available for special applications if you had the need for UV light in your aquarium.

https://www.amazon.com/gp/product/B...f90-526d-a0b6-28c63e1aef71&pf_rd_i=2314207011
$1.51 per star

The biggest issue I see is the fact that you are playing with a light spectrum that is barely noticeable to the naked eye, and difficult for most wet-app sensors to detect so you could easily scorch your coral and not even be able to detect the problem.

 

[2smokes]

Thoose led chips you posted the last, arent UV light .Theyre just pink leds sold as UV but theres zero UV in them.A led chip except thoose made from metal you posted in the first link can not put out any ammount of UV light even if its sold as UV led.I have a device that measures UV and thoose leds measure 0.Uv led chips cant put out UV light because theyr made of plastic and UV damages the plastic fast.Those leds made from metal and glass can make UV but they cost a fortune,they last just 1000 hours and nobody uses them because there are otther better alternatives for UV like MH and neon tubes.The UV led made for lab purposes (the one from metal and glass)is for sale now.Costs like 200 dollars one led.

 

[ksicard]

Thoose led chips you posted the last, arent UV light .Theyre just pink leds sold as UV but theres zero UV in them.A led chip except thoose made from metal you posted in the first link can not put out any ammount of UV light even if its sold as UV led.I have a device that measures UV and thoose leds measure 0.Uv led chips cant put out UV light because theyr made of plastic and UV damages the plastic fast.Those leds made from metal and glass can make UV but they cost a fortune,they last just 1000 hours and nobody uses them because there are otther better alternatives for UV like MH and neon tubes.The UV led made for lab purposes (the one from metal and glass)is for sale now.Costs like 200 dollars one led.

I've been building LED's for several years and I completely agree with your statements. True UV leds wil damage coral. Most LED manufactures brand their leds as uv but they are actually just purple/pink leds.

 

[jayball]

SO my question is in the last two weeks I have seen a number of hobbyists talking about using LEDs in the 650-750nm spectrum to get better growth rate on their corals. Have I been thinking about this wrong, or are they just growing shallow water SPS that need more red light? I just want to build a display that will give me the best light spectrum for good coral growth.

Personally I like to have some warm white (around 2700K-3500K CCT) in my led arrays for supplementing the red end of the spectrum; this is primarily for color rendition. I never feel that dedicated reds are important.
If you have only 10K and up led's than you are very deficient on that end of the spectrum. There is almost no red in a 10,000K LED. Whether or not that is going to greatly affect your growth rates is very much up in the air. I would say not likely unless you find a study that says otherwise.

10 000K has a lot of red in it.If you have white leds i dont think there is a need to add reds (650 nm).Red will help cyano and GHA to grow better in the diplay.And for the shallow water corals like most acropora you could use a perfect spectrum made of all the colors but if its led then you will miss the UV spectrum almost entirely because leds cant make UV light (UVB ,UVC and UVA).For a led lamp i would use mostly royal blue leds as the main source of light and i would add a few ,verry rare red ,blue and green leds.I wouldnt use white leds at all.Green light is useless for corals but its good if you have a yellow fish ,it will make yellow to look yellow not dirt green .

That would make for a very ugly display as you are missing on a lot of the spectrum with only RB and RBG. Reflected colors will not be well represented. You will also be missing the violet end of the spectrum. (not purple(Red plus Blue) or pink(full spectrum white minus green) as violet is a true color)

 

[Ron Reefman]

Reefman - what light is that on the left?

Both fixtures are the new Reef Breeders Photon V2.

The Reef is a 50" and the fuge is a 16". They are made by EverGrow in China. I had 3 EverGrow fixtures (same as the RB original Photon) for 4 years and they still work perfectly. But they are the wrong sizes for the new tanks and I wanted 6 channel control so I could deal with red and green leds by a method other than 100% blackout by covering them with electrical tape! The old EG and RB fixtures are just 2 channel. And the new ones look better (thinner and with legs) plus the program easier with a much better remote.

 

[Ron Reefman]

Your corals don't need true UV. MH fixtures use glass that blocks UV. Only a small amount of UV penetrates water very deep on the reef. Why all the concern about UV?

 

[jayball]

Your corals don't need true UV. MH fixtures use glass that blocks UV. Only a small amount of UV penetrates water very deep on the reef. Why all the concern about UV?

I am going to go ahead and double down on these statements and question.

I agree 100% with what Ron is saying here.

 

[blasterman789]

I've had this conversation with PhD's and numerous marine biologists along with the same analogy on terrestrial plants. Overwhelming opinion is corals don't care about light <450nm (violet extending to UVA). Indeed the most spectacular SPS tanks I've seen lit with LED use nothing deeper blue than standard royals.

Those LED lights I've seen that include violet (390-410nm) LEDs have such a small portion of light in that range that they produce little radiologic growth benefit other than some minor actinic response.

The main proponents of Violet / UVA are T5 or Halide users trying to find a reason to bash LEDs. As early as 10 years ago UVA was regarded as evil in regard to halides and most discussions regarded filtering it.

I don't have time to build my own LEDs rigs anymore, mainly because there's little justification to DIY when chinese black boxes are so cheap. If I *were* going DIY I'd likely have two channels of white with both cool white at 6500k and warm white to balance to taste.

 

[Walla2GSP]

Your corals don't need true UV... Only a small amount of UV penetrates water very deep on the reef. Why all the concern about UV?

I'm not really concerned about it, I know UV is the only type of light that is detectable far after visible light has been lost. I don't see how a small amount could be damaging so I had thought about incorporating one or two UV for every 25 white/blue LEDS, but I'm aware that plenty of people run displays without UV light quite effectively. I just thought it was interesting that people still believe the idea that all cheap UV LEDs only give off "pink-purple" light.

 

[2smokes]

Your corals don't need true UV. MH fixtures use glass that blocks UV. Only a small amount of UV penetrates water very deep on the reef. Why all the concern about UV? I have MH bulbs that can tan your skin in a few hours.UV penetrates the water and its an important part of the spectrum.Corals are iridescent because they evolved to reflect UV light.Corals on reef are blasted with high ammounts of UV .

 

[slief]

Walla, I don't know who or where you saw that adding red spectrum was a good thing or not. In a reef tank, a little red goes a long way. There is some zooxanthellae in our coral that use red for photosynthesis, and corals do use it for production of pigments and other required internal chemistry. I have 6 channel control and over my reef I run zero red or green and 40% white 90% blues and violet. The corals get enough red spectrum from the white leds. Over my refugium I run 100% red, white, green and 40% blues and violet. Macro algae and plants use more red spectrum to do photosynthesis.

+1

Corals get most of their needed photosynthetic radiation from 420nm-480nm with the peak between 420 and 460nm.

As noted, you will get more than enough of the red spectrum from the white channels. Typically a 1:3 ratio of white (6500k) to blue/royal blue will provide a well balanced spectrum for coral growth. The red and green diodes are there primarily to bring out colors in corals that you wouldn't normally see under the 420-460nm (bluer) spectrum. They aren't necessarily there for coral growth. Instead they are there for personal preference and should be used very conservately to avoid promoting nuisance algae growth.

 

[Ron Reefman]

Steve, thanks for confirming my opinions (and some basic knowledge) about light and coral.

2smokes, UV is not visible to the human eye. So coral reflecting UV would also be invisible. Corals are not irridescent (definition of iridescent: showing luminous colors that seem to change when seen from different angles). They are however able to use blue spectrum light and use some of that energy to fluoresce other colors of light back out. It is not reflected, it is fluorescence. End of discussion. I've seen you argue (wrongly) with others in threads here at RC and I'm not going to do it here. :deadhorse: