uv leds ?

Reefs-A-Lot · Aug 4, 2013

Good day,

I'm working with someone to make a new led fixture, and the question of UV lights came into play. Is there such a thing of having to many UV leds (400nm) ?? I want a fixture with 2 green,2red,8uv,15 whites,28 blues.

would the UV be a good idea to have 8 of them- I know they don't provide uva or uvb.

thanks.

Ron Reefman · Aug 4, 2013

UV leds are really violet being 400nm-410nm. And IMHO 8 of them won't hurt anything, but they aren't as useful to the corals as 440nm to 460nm blues would be. And they are quite dim.

c_healy · Aug 4, 2013

Check out hyper violet leds or true violet.

That spectrum appears dim to us as it is almost not visible to the human eye. But it is good for coral, it is what most led setups are lacking as blue and white don't cover that spectrum alone. While t5 and metal halide give off light in that spectrum. I feel it is over looked in a lot of led builds and is beneficial to add in.

calvo15290 · Aug 4, 2013

Ware do you get these to build ?

c_healy · Aug 4, 2013

Ledgroupbuy.com sells them

ReefLEDLights · Aug 4, 2013

Reefs-A-Lot said:
Good day,

I'm working with someone to make a new led fixture, and the question of UV lights came into play. Is there such a thing of having to many UV leds (400nm) ?? I want a fixture with 2 green,2red,8uv,15 whites,28 blues.

would the UV be a good idea to have 8 of them- I know they don't provide uva or uvb.

thanks.

The UV Rock when it comes to spectrum, the problem is they are really dim compared to the 450nm XT-E Royal Blue.

Its about balancing if your 15 whites are Cree X series skip the 2 green you are wasting real estate as the Cree whites all have this spectrum covered. The two red could be replaced by two Warm XT-E and offer better coral growth.

Before you commit. Ask what type of Blues. 445-475nm makes a big difference. I personally like this ratio 6 475nm Blue and 24 450nm Royal Blue...The 465nm Royal Blue will give you less of an actinic look.

Adding 410-420nm would be better than 400. It will not significantly up the PAR but for some SPS will highlight certain pigments.

Bill

Reefs-A-Lot · Aug 6, 2013

thanks for all the replies, this has helped me make my descision easier.i chose to go with the 420NM and some 6.5K led's

ReefLEDLights · Aug 6, 2013

Reefs-A-Lot said:
thanks for all the replies, this has helped me make my descision easier.i chose to go with the 420NM and some 6.5K led's

If you have 450nm Royal Blue with that you will be happy with the results.

Bill

jedimasterben · Aug 6, 2013

ReefLEDLights said:
It will not significantly up the PAR but for some SPS will highlight certain pigments.

This I do not agree with. In my testing with true high-output violet LEDs, they are absolute PAR monsters with optics. A dozen of them will hit 150 PAR at 700mA, 24" from the sensor, with 60 degree optics. That's not a number to take lightly. Generic chinese ones will have around half that, but still respectable, especially for sitting at the absorption peak of chlorophyll a (428nm). PUR is 100% with them, royal blue is actually lower in PUR since corals do not contain chlorophyll b (peaks at ~452nm) and contain small amounts of chlorophyll c (about the same absorption spectra as chlorophyll b), around 10% of their chlorophyll a content.

As far as pigment excitation, those are few, and any fluorescence from them specifically will be drowned out when any other type of LED is turned on, whether it be a white, royal blue, etc. Violet are catching up to royal blue in output - the highest are averaging 920mW of output at 700mA, compared to an XT-E royal blue, Q bin, with ~1,050mW, and a Luxeon Rebel ES royal blue, M bin, with ~1,150mW (adjusted to 85Â°C).

ReefLEDLights · Aug 7, 2013

jedimasterben said:
This I do not agree with. In my testing with true high-output violet LEDs, they are absolute PAR monsters with optics. A dozen of them will hit 150 PAR at 700mA, 24" from the sensor, with 60 degree optics. That's not a number to take lightly. Generic chinese ones will have around half that, but still respectable, especially for sitting at the absorption peak of chlorophyll a (428nm). PUR is 100% with them, royal blue is actually lower in PUR since corals do not contain chlorophyll b (peaks at ~452nm) and contain small amounts of chlorophyll c (about the same absorption spectra as chlorophyll b), around 10% of their chlorophyll a content.

As far as pigment excitation, those are few, and any fluorescence from them specifically will be drowned out when any other type of LED is turned on, whether it be a white, royal blue, etc. Violet are catching up to royal blue in output - the highest are averaging 920mW of output at 700mA, compared to an XT-E royal blue, Q bin, with ~1,050mW, and a Luxeon Rebel ES royal blue, M bin, with ~1,150mW (adjusted to 85Â°C).

What type of PAR Meter are you using? Also what spectrum Bin of the Cree XT-E are you using? There is a difference between group D36 and D57.

I've tested a Mix of 45 Cree Royal Blue, Blue and Cool White LEDs driven at 700mA on a 18"x 8.46 heatsink at well over 500 PAR 24" from the sensor with Carclo Ripple wide Optics and 290 PAR using 90 degree reflectors...

I'm shocked that you dont agree...

[video=youtube;SjbPi00k_ME]http://www.youtube.com/watch?v=SjbPi00k_ME[/video]

Cheers

Bill

jedimasterben · Aug 7, 2013

ReefLEDLights said:
What type of PAR Meter are you using? Also what spectrum Bin of the Cree XT-E are you using? There is a difference between group D36 and D57.

I've tested a Mix of 45 Cree Royal Blue, Blue and Cool White LEDs driven at 700mA on a 18"x 8.46 heatsink at well over 500 PAR 24" from the sensor with Carclo Ripple wide Optics and 290 PAR using 90 degree reflectors...

These were measured by a third party at ~453nm peak, so I'm assuming D37. The difference between wavelengths in such narrow-bandwidth LEDs, frankly, do not matter and do not change the output to any measurable amount outside of the margin of error. I've tested several XT-E royals from several wavelength bins, and none from the same flux bin are any more powerful than another. Rarely will you find a royal blue XT-E higher than ~455nm.

Blue and cool white light up a PAR meter (and are both orders of magnitude brighter to the eye), but PUR on them is lower than royal blue, and much lower than violet. You'd need to measure them separately or you will not get accurate results.