UV LEDs in Radions and bacteria

[dvlpr]

This may sound like a silly question and I suspect I know the answer, but I wanted to re-confirm.

So, my lights have 4 UV LEDs at 405 and 415nm. These should not be harmful to bacteria (beneficial and other), since UV wavelength that kills bacteria is in the 255-280nm range - is that a correct assumption? Thus these LEDs are there simply to bring out some colors in some fish/corals and won't affect the chemistry of the tank, right?

I'm asking because I'm cycling and have the lights on (purely for visual effects), but at some point I had this thought crawl into my head - "hang on a minute, there's UV on them, what if it's killing off my nitrifying bacteria?", but I'm safe, right?

 

[RandyC]

This may sound like a silly question and I suspect I know the answer, but I wanted to re-confirm.

So, my lights have 4 UV LEDs at 405 and 415nm. These should not be harmful to bacteria (beneficial and other), since UV wavelength that kills bacteria is in the 255-280nm range - is that a correct assumption? Thus these LEDs are there simply to bring out some colors in some fish/corals and won't affect the chemistry of the tank, right?

I'm asking because I'm cycling and have the lights on (purely for visual effects), but at some point I had this thought crawl into my head - "hang on a minute, there's UV on them, what if it's killing off my nitrifying bacteria?", but I'm safe, right?

they won’t kill any bacteria. You’ll be fine leaving the lights on in terms of bacteria not dying. And yes you are correct, you’ll need to be below the 300nm spectrum to really start doing some damage. Now algae growth, that’s a different subject.

 

[dvlpr]

they won’t kill any bacteria. You’ll be fine leaving the lights on in terms of bacteria not dying. And yes you are correct, you’ll need to be below the 300nm spectrum to really start doing some damage. Now algae growth, that’s a different subject.

Thanks for confirming! Coming from FW - I had a UV filter running there 24/7 and it has helped me heaps, but here, in SW territory, I won't need one from what I can see and even can introduce the tank to some sunlight, which was a no-no previously. Lots to take in

 

[jda]

That are not UV. UV is below 400nm and if you want to sterilize anything, you must go a lot lower than that. There are spectrums down to about 350 in some T5 and MH bulbs and nearly all of them get to 375-380 and have some real UV and they are plenty safe.

Those are violet LEDs. It is a LED manufacturer "white lie" about their products... except for Orphek which does use real UV in some of their units.

 

[Hydrored]

Thanks for confirming! Coming from FW - I had a UV filter running there 24/7 and it has helped me heaps, but here, in SW territory, I won't need one from what I can see and even can introduce the tank to some sunlight, which was a no-no previously. Lots to take in

I would be hesitant to introduce the tank to sunlight, only in the spring the corner of my tank gets hit with sunlight and it grows a bit of hair algae only on that spot.

 

[dvlpr]

That are not UV. UV is below 400nm and if you want to sterilize anything, you must go a lot lower than that. There are spectrums down to about 350 in some T5 and MH bulbs and nearly all of them get to 375-380 and have some real UV and they are plenty safe.

Those are violet LEDs. It is a LED manufacturer "white lie" about their products... except for Orphek which does use real UV in some of their units.

Yes, it is confusing when they say UV, but thankfully they also specify the wavelength, so at least we can do some research and confirm what they do (and don't).

I would be hesitant to introduce the tank to sunlight, only in the spring the corner of my tank gets hit with sunlight and it grows a bit of hair algae only on that spot.

But that's free food for the CUC