UV Safety

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Aquarium Advice Newbie
Jul 16, 2023
Good morning

How much UV is produced by the UV bulbs used for aquariums, specifically the lights that sit above the tank outside the water?
I worry about skin cancer and know how dangerous tanning bulbs are so am curious how safe the lights used for fish tanks are. I recently sat next to a large fish tank which had what appeared to be a fluorescent tube over the top of and outside of the actual tank with a bit of plastic separating it from the water. I was able to see it through the tank glass and this bit of plastic so hoping this plastic and glass also protected me from any potential risk.



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Sitting next to UV for a short period of time isnt going to be any risk. Sitting near a window, even on a cloudy day, will expose you to far more UV than sitting next to a UV light.

UV light used in aquariums are generally sealed units where water circulates in a closed container, or put into sumps to ensure whatever is living in the tanks arent exposed to the UV, so it sounds like the light you sat next is just an aquarium light with no UV anyway.

Some people keep glofish under blacklight, which is UVA and much less hazardous than UVB, and well below hazardous levels. Same for plant growth bulbs, although plant growth light often contain a little UVB. I wouldnt want to sit under one hour after hour, day after day, but sat near one for short periods of time is of no risk. There are far more worrying things out there.
Ok great thanks, I’ve managed to add an image I’ve found now. Do you not think this is actually producing uv then since it is outside the tank?

Its just a normal aquarium light. There will be very little if any UV. The lights in the room will be more harmful to you as you are sat directly below them.

Next time you go back there tell them they need to fill up the water level in the tank.
Phew thank you I just assume that’ because it was blue it was emitting uv which then triggered my anxiety.
That photo is 5 years old I just found it on Google for the restaurant to show what it was like, last night the light actually looked a little duller and there were less fish.

Thank you
It looks a little actinic, but that just means it has more blue wavelength light in it. You cant actually see UV, so you cant visually determine if a light has a UV component or how much. Actinic light is less energetic than UV and is often used in marine lighting as algae that live within, and coral depend on, need the blue wavelength.

If you are really that concerned the only way to know is go back and take a look at the light tube. There should be some marking that tells you whether its a UV tube. But generally the lights used to illuminate aquariums have no more UV than the lamps everybody has in their kitchen and compared to what UV everyone is exposed to on a daily basis from natural light and typical light fittings is negligible. If it was a genuine UV light the fish would be suffering from noticable cancerous issues and dying on a regular basis.
Just to give you a little more comfort, this is the light spectrum from a 14000k aquarium light that would be typical in a marine aquarium and suitable for coral (for info the aquarium you sat next to is freshwater, so the light isnt the best choice for FW).


You can see the spike of blue spectrum light that gives it the actinic appearance and is useful to those corals i mentioned. The spike drops off dramatically as the wavelengths go into violet and ultra violet as these wavelengths are less useful and the UV would actually be harmful. While im sure the spectrum continues to the left and contains some UV, it will be very little and no more than typical artificial light.
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