UV LEDs, why??

[Saltydrip]

Why do we need/want/use UV LEDs in our setups?

I have been experimenting with different LED colors and wave lengths and just picked up some UV LEDs. They are cheep radioshack LEDs but I just wanted to see what the look like. 2 for $2 so why not. They don't do much for coloration in the tank but then again I have a 55g that's on the deep side and these cheep LEDs are a little weak.

[jtrim123]

UV doesnt do much as far as visible color. It does however give a wavelength vital to growth and coloration.

[Jeff000]

UV doesnt do much as far as visible color. It does however give a wavelength vital to growth and coloration.

Vital eh? Except many systems grow corals just fine without any uv. T5 and double ended mh tend to disagree, e with the huge amount of diy setups that don't use uv,

Uv is harmful to just about everything. If you look at the spectrum analysis of what coral need you'll see that getting into the uv range isn't utilized.

[Revmedia]

Well now I'm thoroughly confused. Half the people I hear saying UV is great for corals, while the other half say its a waste or harmful.

I'm about to customize a set of LED fixtures, and I need some input on this.

[mussel and hate]

We don't really use UV LEDs. Ignorant people dub these violet LEDs UV.

Violet and/or nearUV LEDs contibute to fluorescence and photosynthesis which is why we use them.

Fluorescent and Metal halide lighting however do produce significant UV output as they are mercury arc lamps.

You guys have it all reversed and mixed up.

[Bigcefa]

It's about the wavelength bra

[Lavoisier]

Strongly recommend you read this article, then go to his website and read, read, read. His work is thorough and tested.

http://www.advancedaquarist.com/2012/3/aafeature

[Revmedia]

Aha, now I feel like I understand this a bit better. That link is great.

[Saltydrip]

Thanks for the link. I'll do some reading.

[oupulino]

Nice info guys what about Red and Green looks like is not just cosmetic touch .I'm on same page like Saltydrip looking to get more richer color on my set up

[SWKustoms]

I have read in a few places about coral coloration and UV. I don't recall the specifics but corals change colors due to the lack of UV. I think the brighter and vibrant the color is the defense the coral uses to block UV and if UV is not present the coral will tone down their color or it will completely change color. I think LPS are very well know for this change.

[jerpa]

Most of the pigments that protect them from true UV are clear. The LEDs we are speaking of are much more comparable to a VHO/T5 Actinic bulb with peaks generally between 385-420. Based on anecdotal evidence I would guess those wavelengths impact coloration.

[Jeff000]

We don't really use UV LEDs. Ignorant people dub these violet LEDs UV.

Violet and/or nearUV LEDs contibute to fluorescence and photosynthesis which is why we use them.

Fluorescent and Metal halide lighting however do produce significant UV output as they are mercury arc lamps.

You guys have it all reversed and mixed up.

I think you might be mistaken. Or we are all talking about different UV.
UV as in UVA and UVB are well different than near UV violet spectrum (UVC i think it's referred to?).

T5 do not give off UVA or UVB in any significant quantity (If at all). Nor does a DE MH bulb, especially given that MH almost all use a UV filtered glass.

[mussel and hate]

I could be mistaken. The OP really could be considering ulta violet LEDs although that would be really expensive and of questionable benefit.

Most of the LEDs referred to as UV possess spectral peaks above 400nm which makes them violet or near UV not ultra violet(UV).

T5s and other fluorescent lights are mercury arclamps as are metal halide lamps. Both emit significant amounts of UV (yes, even with a filter).

I hope that clears things up.

[Jeff000]

T5s and other fluorescent lights are mercury arclamps as are metal halide lamps. Both emit significant amounts of UV (yes, even with a filter).

I hope that clears things up.


A typical cool white fluorescent tube spectium
http://1.bp.blogspot.com/-zqK50LhkCyk/T-Hg-9mQwCI/AAAAAAAAAMQ/10q5zZLk64k/s1600/figure4.png
notice almost nothing below 400nm

And here is a purple plus
http://glassbox-design.com/wp-content/uploads/2010/07/ati-purple-plus.jpg
Again nothing really below 400nm

Pure attinic maybe?
http://www.practicalcoralfarming.com/images/t5lighting/giesemann%20pure%20actinic.jpg
A little below 400nm, but hardly.


MH, little harder to find, and non really say DE or not. But they all fall on their face at 350nm. Can't find any readings through UV filtered glass. But I have no reason to think that the uv filtered glass wouldn't filter 100% like every other uv filtered glass out there.
Here is one that goes the most into UV outside of UV specialty bulbs.
http://www.advancedaquarist.com/2004/2/aafeature1_album/figure6a.jpg

[MHG]

I have 3 420nm led's in my front strip. I like the color. You cann see the difference for sure.... Gonna add another 6 in my main light...

[Jeff000]

I have 3 420nm led's in my front strip. I like the color. You cann see the difference for sure.... Gonna add another 6 in my main light...

Just remember, 420nm is not UV.
It is where MH and the sun peak though.

[theatrus]

True UV LEDs are amazing inefficient, very expensive ($100+ for germicidal wavelengths), and very dangerous.

The violet LEDs in the 400-420 area however cause all sorts of nice fluorescence.

[Saltydrip]

The LEDs I got from radio shack were $2 for a 2 pack. They emit a very violet light. I'm unsure on the actual wavelength because that info just isn't made available. They are the standard old fashioned bubble type.

[mussel and hate]

True UV LEDs are amazing inefficient, very expensive ($100+ for germicidal wavelengths), and very dangerous.

The violet LEDs in the 400-420 area however cause all sorts of nice fluorescence.

^ This

@ Jeff,

In each of the graphs you've posted there is a little peak around 365nm. That my friend is UV. If you wan't to see some MH graphs then check the link Lavoisier posted to Sanjay's article in Advanced aquarist.

[Jeff000]

^ This

@ Jeff,

In each of the graphs you've posted there is a little peak around 365nm. That my friend is UV. If you wan't to see some MH graphs then check the link Lavoisier posted to Sanjay's article in Advanced aquarist.

Yes it is uv, very tiny amounts with no intensity. Which is why I said there is very little. There isn't enough uv in a standard cool white fluorescent tube for your skin to react to it.

And also when the glass shield of a mh says 100% uv filtered there is no reason to doubt it, Uv protective glass is not new, and is very reliable.