Blacklight????

del is right on on this one. Black light = UVA, if it were UVB, there'd be a lot of skin cancer patients suing the producers of those lights. UVB even at low wattages can give you a sunburn in minutes, it can cause blindness and also skin cancer.
Why can't everyone just knock it off with the UV? The tubes needed are not exactly safe, the government actually has safety standards for mh and HPS bulbs and they aren't allowed to emit a certain amount of UVB, HID bulbs are specifically coated to decrease the amount of UVB. And I keep hearing about folks who don't know what they're doing wanting to supplement with this stuff.

If you really want to supplement with UVB (first off the tubes are gonna be expensive, cheap lizard lights or black lights won't cut it, they are mostly UVA) you should have it hooked up so that if anyone opens the door it shuts off automatically, or you need some sensor to tell you whether it's on or not cause you won't be able to tell. (UV is shorter wavelength than visible so we can't see UV radiation, you can see a little blue tinge on the bulb, but you shouldn't be in the room with a lit UV bulb let alone staring at it.

Hell, I'd toss out the black light as well. UVA is getting a worse and worse rep. UVB is higher energy which means higher frequency and shorter wavelength (freq and wavelength are inversly proportional), they have more energy but can't penetrate as far. UVA is dangerous because it penetrates further into the skin layers. The more research that comes out the more they say you should probably limit exposure to both types of UV radiation.