UV leds. Is there any new information out there

[dave willmore]

Great thread. My tank is in a polycarbonate greenhouse. After I built it I read in Anthony Calfo's coral propagation book to get as much UV light onto corals as possible. But my polycarbonate, like everything in the greenhouse business is U/V shielded. So I may need to supplement the 400 to 420 um range with LEDs as you guys are saying.

So I'm very interested in your recommendations for light that stimulates color. Most corals in greenhouses tend to brown out in the sun and I've not heard a clear answer why. I guess they use brown "sunscreen" because sunlight is too intense for deeper water corals which we keep at just a foot or two of depth.

 

[Mxx]

There is it seems a special plastic which they use for sunbeds which doesn't filter UV light, so you could reclad your greenhouse with that!

I read that browning out appears to be caused by creating conditions which are very favourable for the algae which coral contain, ie the combination of nutrients, light, etc.
Here is a comprehensive article on light in regards to coral colour - https://reefworks.co.uk/articles/obtaining-the-best-colours-from-your-corals/

 

[dave willmore]

What this article appears to be saying is that high nutrient water makes brown zooxanthellae increase and masks the bright colors. It also seems to say that lack of food increases colors in the short run while starving the coral in the long run. And it says that the verdict is still out on trace minerals. Do I have it right?

If so, the answer would be low nutrient water that still has adequate food levels, which I think is the fundamental challenge in all reefkeeping.

 

[Mxx]

What this article appears to be saying is that high nutrient water makes brown zooxanthellae increase and masks the bright colors. It also seems to say that lack of food increases colors in the short run while starving the coral in the long run. And it says that the verdict is still out on trace minerals. Do I have it right?

If so, the answer would be low nutrient water that still has adequate food levels, which I think is the fundamental challenge in all reefkeeping.

Starve your corals to death to achieve their best coloration, I like that! :eek2:

That seems to be kind of the approach used with these ULNS, which some use to impressive effect.

Can you feed your corals decently while still keeping the water very lean, without having them brown out as well though?

 

[dave willmore]

Actually my tank is an experiment in just that. By removing nutrients with a settlement chamber instead of a skimmer, a constant drip of live zooplankton may give the best of both worlds -- low nutrients at the same time as ample food.

But it may also fail completely. I'll let you know in a year.

The relation to this thread is that if nutrients have as much effect on coral colors as light wavelength, all the factors need to be addressed in combination. Perhaps more light in the 420 nm wavelength will not help if color loss is caused by excessive nutrients to the zooxanthellae. I don't know, I'm just learning.

 

[rtparty]

Great thread. My tank is in a polycarbonate greenhouse. After I built it I read in Anthony Calfo's coral propagation book to get as much UV light onto corals as possible. But my polycarbonate, like everything in the greenhouse business is U/V shielded. So I may need to supplement the 400 to 420 um range with LEDs as you guys are saying.

So I'm very interested in your recommendations for light that stimulates color. Most corals in greenhouses tend to brown out in the sun and I've not heard a clear answer why. I guess they use brown "sunscreen" because sunlight is too intense for deeper water corals which we keep at just a foot or two of depth.

True UV lighting is bad for corals. You should NOT blast them with true UV.

400nm to 420nm is NOT UV light. It is violet, or Actinic, light. In the hobby we refer to the lower end of the spectrum as Actinic light as you can see with Actinic VHO and T5 bulbs.

Corals use a pigment to protect themselves but it is clear, not brown. The brown you see is from the zooxanthellae algae. Zooxanthellae algae LOVES the sun and thus corals tend to look more brown under the sun. Another part of the problem is that sunlight doesn't cause corals to fluoresce like we are used to in this hobby.

If you are having issues with brown corals, add some Blue light to your setup or put some type of blue filter screen in your greenhouse.

 

[gbru316]

Calfo actually said shading was necessary on his greenhouse outside of Pittsburgh in his book

 

[007Bond]

Subscribing very good info.

 

[dave willmore]

Calfo actually said shading was necessary on his greenhouse outside of Pittsburgh in his book

But Calfo also said to give the corals as much UV as possible, which confuses me because he didn't specify between UV A, B, or C. At least not in his coral propagation book of 2007.

 

[dave willmore]

If you are having issues with brown corals, add some Blue light to your setup or put some type of blue filter screen in your greenhouse.

I will. The tank actually won't be ready for water until a few more weeks but I've heard of using blue plastic to reduce PAR. But help me out. Every coral has pigments based on it's genetics, its just a matter of the light levels that mask or unmask the pigments already there, correct?

 

[josephv]

Ok I have just installed 5 new violet uv leds in the 410--420 nm wave length and 5 cree xp. E green leds in the 520--535 nm wave length. Time will tell as to how the corals react to the new lights but the effect of both the new leds is striking. When viewed singularly the green are very strong and add a hi def look to the tank. The uv violet are not that bright but really light up the fluorescence in all the corals. To recap I now have 128 --18000-20000 k fedy white leds. 48 feddy royal blue. 6 red and the 5 new green and uv leds on my 300 dd tank. I have all the different colors on serate drivers so I can add or take away all the colors indiependently. Hope the corals enjoy the new depth of color as much as
I do.

 

[m&m1318]

lol Juz call me a noob & have a few Questions. I dont understand if the leds are true primary colors, as an red, blue, yellow. If so Why can't they make a circle Puck of the primary colors with a light reflector a flashlight have,also throw in your white, and black (uv). Because my understanding is that the primaries change all colors. Maybe im dumb here or something, but thats what I was taught in art school, but maybe its different in this situation. I have 84 white leds in my aquarium & 32 blues, But my aquarium doesn't show any blue tint when they're all on. So my question is do u think it'll work.

 

[scolley]

Ok I have just installed 5 new violet uv leds in the 410--420 nm wave length and 5 cree xp. E green leds in the 520--535 nm wave length. Time will tell as to how the corals react to the new lights but the effect of both the new leds is striking. When viewed singularly the green are very strong and add a hi def look to the tank. The uv violet are not that bright but really light up the fluorescence in all the corals. To recap I now have 128 --18000-20000 k fedy white leds. 48 feddy royal blue. 6 red and the 5 new green and uv leds on my 300 dd tank. I have all the different colors on serate drivers so I can add or take away all the colors indiependently. Hope the corals enjoy the new depth of color as much as
I do.

With all that light you are throwing at that tank I'm really surprised the just 5 violet uvs can make that much of a difference. In my testing of violet uvs it seemed like I'd need a lot to make a dent in the 24 xr-e RB/blue/white I throw at my tank. So I'm surprised just 5 makes a visible difference.

 

[gbru316]

With all that light you are throwing at that tank I'm really surprised the just 5 violet uvs can make that much of a difference. In my testing of violet uvs it seemed like I'd need a lot to make a dent in the 24 xr-e RB/blue/white I throw at my tank. So I'm surprised just 5 makes a visible difference.

correct me if i'm wrong RT, but violets aren't intended to alter the visible portion of light. To do so would require a large amount of violets. Rather, the pigments in the corals react favorably to the addition of violets (even though we don't notice it much), which we CAN visibly notice.

 

[scolley]

correct me if i'm wrong RT, but violets aren't intended to alter the visible portion of light. To do so would require a large amount of violets. Rather, the pigments in the corals react favorably to the addition of violets (even though we don't notice it much), which we CAN visibly notice.

That downstream effect you mention may be true. I would not know. But I do know that if I hold a violet LED close to a coral, its colors pop. But its got to be close to see the effect, which is why I'm surprised that so few can be noticeable to someone,

 

[josephv]

The 5 uv violet look to cool when all the other lights are out and are great lunar lights but have little effect to the naked eye when all the other leds are on. Royal blue make the color pop but the uv violet increase the effect When only royal blues are on then adding the violet the affect is noticable. I wanted to use a small amount of uv just in case the corals and livestock dont like it. Better safe than sorry. I will tell you this. The red and green leds add a whole new depth ao color to the tank. Love it
Hope the coral and livestock enjoy it as well.

 

[scolley]

Thanks for the clarification. IMO you should be able to see that pop that the UV violet add with all the other lights on, but it would take a LOT more of them.

 

[MHG]

I added just 3 of the 410-420nm 3x led's from rapid and I love them...

 

[rtparty]

correct me if i'm wrong RT, but violets aren't intended to alter the visible portion of light. To do so would require a large amount of violets. Rather, the pigments in the corals react favorably to the addition of violets (even though we don't notice it much), which we CAN visibly notice.

Haha, I won't correct anything. I am not an expert in this game.

For me, I don't see my UV LEDs at all if ANY other source of lighting is present. I mean even a small amount of daylight from my window washes them out. BUT, I can tell that my corals "see" the UV light because they perk up a little bit.

I plan to run 3-4 UV Stunners on my new fixture because I like what they have done so far. I bought a totally browned out SPS from my LFS and I think it may be a Tri-Color. It has the brightest green polyps and all the tips are turning a nice purple color. Only time will tell. It has been in the tank about 3 weeks as of today and I personally have never had color change this quick on SPS. At least not in the positive....

 

[Patzig]

I added 3 "uv leds" (the rapid led 410-420 nm) to my total 36 led fixture and hardly noticed a difference. It barely adds almost a black light effect, and just gives the brighter colors a little more pop. My thinking in adding the ~420 nm leds was trying to replicate t5's in a way. Most t5 fixture have at least one "true actinic" 420 nm bulb. I think the effects of adding these violet leds will mostly be seen in the long run.