Black light?

So i bought a couple black lights by the brand "eco light"  for our haunted house last year and only used them for a total of a couple hours but they are way cool to mess around with and i put them over my tank when i turned the lights off for a sec and all my corals or most of them glow:)  So i went online and in some websites people say they are bad, but some say there not bad but not good, they just make the colors pop. So what  i am asking is are they bad to use in general or can i use them to make the colors pop?? When i did it, they didnt close up so i dont think it was hurting them...... Opiinions, tips? Have anyone else seen corals (zoas, frogspawn, clovers) under it? Looks pretty cool, but i dont want to do it if its bad so any help would be appreciated, Thanks! (sorry for the long post)    - Tanner

black lights can actually cause your fish to go blind. just some helpful info ive learned over the years.

I would say one of those at your own risk things.  Can only imagine what it looks like though. 

Its not hard at all to see it. Last night i did it for an hour and my corals looked like something out of the movie avatar! They look sooooooooo Cool glowing with the black light. The radioactive dragon eyes are neon green x10000. The frogspawn has never looked so purple and green, and the clovers get the brightest neon greenish purple. Hard to describe. I did more reasearch and the light spectrum doesnt help the corals nor hurt them, just shows them off. And for the fish - still debating. I have herd that its not good for thier sighting, but it looks just like the moon light at night with a blue glow through the water, but at the same time - a lot of websites that i check out says it doesnt do anything to corals nor fish. There is no benifiting or hurting. Also one more thing i realized which i think is Efiing wierd is when i turn off the black light, the dragon eyes zoas still glow for 10 secconds!!!!!!!!(not as bright)So cool!!

Just get a t5 light at the 453 spectrum. Almost the same thing and safe on corals and fish. Also regular moonlight leds make corals glow too.

Your commercial black lights are UVA black light.  Probably in the 300 - 400 nm range.  UVA is the least harmful of the UV rays and is visible to us(between 300 nm and 315 is visible to our fish but not us).  Some UV rays(UVB) are helpful in the formation of vitamin D which is beneficial and found in natural sunlight but, as when we get sunburns, over exposure can be harmful.   UVC is the most dangerous, with the highest energy, and is used in UV sterilizers to sterilize microorganisms thus rendering them harmless. 

Edited by Soehl - June 29 2012 at 12:43pm

You're welcome!

Maybe just adjustment to a night cycle...