UV Channel?

Jeremy K.A. · May 15, 2018

Hey everybody! I'm curious what you run your Ultraviolet channels at on your LEDS etc.
I'm also confused as to the importance of UV and how high or low we should run it?
What are the benefits or problems caused by it?
I have 2 AI Hydra 26's on my 55

biophilia · May 16, 2018

I run the UV channel (which i really "near-UV" at 405nm) all the way up (119%) on my AI Prime HD as per the BRS settings which aim to replicate Ecotech's AB+ lighting profile. Cranking it up to match whatever percentage you run for your brightest blue channel is fine. It's a pretty important spectrum used by zooxanthellae in my opinion -- and encourages fluorescence.

Jeremy K.A. · May 17, 2018

biophilia said:
I run the UV channel (which i really "near-UV" at 405nm) all the way up (119%) on my AI Prime HD as per the BRS settings which aim to replicate Ecotech's AB+ lighting profile. Cranking it up to match whatever percentage you run for your brightest blue channel is fine. It's a pretty important spectrum used by zooxanthellae in my opinion -- and encourages fluorescence.

Really? I thought I've heard people say not too run it very high in the past

hart24601 · May 17, 2018

I don't know why people say that. IMO it's one of the better parts of the spectrum that LEDs finally have (tied with violet). I always run it at my highest blue setting. I will not use an LED without near UV.

biophilia · May 17, 2018

I think part of the reason people are fearful of the near-UV/405nm spectrum LEDs is that in their erroneous association with the UVB (280-315nm) light that causes sunburns, skin cancer, etc in people. The diodes used in the AI LEDs are basically just a "UV-ish" violet light that encourages the development of fluorescent proteins in coral.

jda · May 17, 2018

It can do several things.

First, it is in the spectrum that a lot of proteins get energy from. Most of them, actually. UV above 350nm (UVA is good for corals).

Second, the input of true UV below the visible range of 400nm can be absorbed by the coral, have energy used and then spit back out at slightly lower energy, which can be in the visible range. If you want to see deep violets, purples and blues, then you will get better results using true UV light. All light that is used for energy will be emitted at lower energy, so you have to "aim low" with your targe.

Third, the gold-standard light source for reefing has a good amount of UV. Check out some charts from the best-of-breed MH bulbs like 20K Radium or 14k Phoenix from 350nm to 850nm and you will see both UV and IR that are not being considered essential after being forsaken for a decade of LED development.

Fourth, the "hubris of man." People discount UV because it cannot be seen. Most meters (including PAR meters) do not capture any of it and just focus on general lighting, which is were too many assumptions and information is gleaned from. Just because it does not have any real impact on humans generally leads to the backwards paradigm of having to prove that corals need it, rather than the correct way of thinking that adaptation and evolution have developed corals that use what is in nature.

In short, UV is important... it is one of the reasons that MH still illuminate and grow coral better than LEDs. More and more LEDs are getting true-UV every - people are enjoying these lights better than previous generations.