What spectrum is a "blacklight", close to actinic?

[becon776]

Was sitting here thinking... I see at walmart they have those t12 "blacklights" I remember those things from college dorm room days... what spectrum are those anyway? wonder what one would look like over a reef tank. THey are only like 15 $ I think that they are even darker than actinics. Just seein if anyone had ever even tried this.

heres another story, along the same lines. Last night I came home from a lacrosse game only to see my roommate sitting in front of my tank (all the light were off) drinkin a beer and he had his strobe light against one of the sides of the tank. At first I freaked but then sat down and watched it recalling the good old days... :bum: the clown fish were actually drawn to it. Now he's tryin to get me to mount it into my canopy. I mide as well hang a little disco ball from the center brace.

 

[becon776]

yah... tried to do a web search on the subject but only one poster and it didn't really say anything of consquence. Anyone?

 

[EQCM2B]

I asked this on another forum a while back and was told that blacklight was bad for people let alone fish. Something about a certain UV light that they give off is very bad. HTH

 

[fat-tony]

It's below the visible light spectrum (UV) while Actinic is toward the very bottom. would assume it's not the best for the fish since a UV sterilizer itself is self-enclosed and completely hidden from eye-sight.

 

[Stephany]

A black light bulb produces UVA light (as opposed to UVB light, which is much more harmful). It's the least harmful out of all UV lights, and is used all over.
UVA = (300-400 nm) used in light therapy, tanning booths, spencers
UVB = (280-315 nm) causes skin cancer, this is why we *want* the ozone layer.
UVC = (100-280 nm) absorbed in air, purifies air and water.

We've got a spectrum that goes from like, 100 nanometers to 1,000,000 nanometers.
At the left end are x-rays, and then UV light (100-400 nm) we can't always see.

Then there's the visible light spectrum from 380-770 nm.

Then there's infrared at the right end, 780-1,000,000 nm.

It's a reverse rainbow.

 

[Stephany]

And green beer makes people do straaange things. I got a call from my sister yesterday who rode the mechanical bull at Daisy Duke's calling me a wuss for not coming out.
I don't think a black light will hurt a thing, your stuff will glow though. I'm not a big fan of tanks with actinic-itis, but as lunar lights it would be kinda cool.

 

[spoon25]

blacklights make the water look muddy....they dont work making colors of corals come out....true actinics do....and since those bulbs are only like 12 watts or something, its not powerful enough to harm anything....it wont penetrate 3 inches into the water, let alone make it look so dirty and muddy.....too bad thoough i would love to pay less then 20 bucks for bulbs if they worked....

 

[Guy]

I did a 2 month experiment with Black Light. During the experiment (4 X 20 watt Black light over a 10 gal) none of the corals died. Some thrived (orange & green corals), other stopped growing (I assume from lack of usable light).

My unscientific conclusion is that they are not harmful but not all that useful either except for corals that flouresce green or orange. Something in saltwater flouresces white and makes the water appear very cloudy.

 

[dalbrecht]

Several people have experimented with UV moonlights as well. The main issues are two fold.

I think with the low wattage of a 24" t 12 in relation to the rest of the lighting over a typical reef they should be relatively safe. UV radiation has the deepest penetration in marine environments and coral from deep waters still have protection.

 

[Guy]

In this pic you can see how cloudy it makes the water. The tank is perfectly clear without the Blacklight.

The coraline flouresces like crazy though.

 

[jcanute]

cool pic.