LED UV Question

[JustinGr]

I have a question in regards to UV from LED lights.

My experience of using LED lights comes from illuminating art and antique artifacts, and it has always be recommended (since they became common place to purchase) that you should use LED lights on art because they do not produce UV, because UV will fade paint and fabrics.

For example, I use a small LED light on a case I have for an 18th Century Japanese Samurai Armor in my sitting room. https://picasaweb.google.com/104054299888891235469/ArmorCase?authuser=0&authkey=Gv1sRgCL27sPODrIWCSw&feat=directlink . The LED lights, while not on all day, are said to produce no UV and thus safe for display.

So, this brings me to my question(s) do LED's produce UV, do we need the UV for corals? If so, are these special LED UV producing lights?

Thanks!

 

[jcm2m9]

They are misnamed. They are not true UV. They are actully violet.

Hope this helps.

 

[nvdiz]

I was actually just wondering the same thing this morning... thanks!

 

[rtparty]

Typical white and blue LEDs do not produce any UV, that is true. LEDs are a very narrow spectrum type of light.

There are UV LEDs out there if you look for them. UV stands for Ultra Violet and is typically light below the 400nm range although UV light really starts about 380nm. It just so happens that the human eye doesn't see 380nm light that well, if even at all.

Do corals need UV light? That is a topic up for discussion. Some experts say yes and others say no. Who do you believe?

I am not an expert and have no letters after my name to validate my statements but I do have some experience with near UV lighting. I run an Ecoxotic 403nm Stunner strip over my tank and have since Novemberish sometime. Within a couple days of adding the new light, my corals were puffier than usual and started showing some colors that I lost with LEDs. After about 5 weeks or so I hit a plateau though and colors started diminishing in my tank. I thought LEDs were the total blame here and was ready to sell them off. I bought a brand new halide setup and was ready to replace my lighting as soon as I find time.

I decided to give the LEDs a few weeks and really watch my water parameters again (I had gotten somewhat lazy). Well after 2 weeks, nothing had really changed and colors were browning even more. I figured out that water quality wasn't my issue so what could it be? What are the usual factors for browning corals? 1) Nutrient issues 2) Lack of light intensity.

I decided to up my photo period on my LEDs and allow my mid day lighting to run longer. Within days my corals responded positively. They started showing feeding habits at night which I hadn't seen in a while. I have since continued to add on time and things are progressing very well for me. I have stayed on top of testing and water changes and it is paying off. I am now ready to sell off my halide setup or hope the LFS will take it all back!

Sorry, I didn't mean to turn that into an "LED history of Ryan's tank" but I felt I needed to include it all. I personally feel that the UV stunner strip I added has done wonders for my tank. When I get my new tank and new fixture, I will add a couple more UV stunners to help spread the light around.

 

[JustinGr]

Thanks Ryan. Very helpful!