Snakes and other reptiles can not see the red spectrum of light, it's too low for them to see. I actually had a blacklight on my black rat for a while at night, before I got a red light. It didn't seem to bother her that much, but I wouldn't do it again.
How close to the tank are your blacklights going to be?
and a regular incandescant screw in bulb will NOT give you a true "blacklight"...i.e. the one that makes white shirts glow purple. you HAVE to get a flourescent for that, because you are looking at a totally different type of gas going through that.
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The reason mainstream thought is thought of as a stream is because it's so shallow. -Unknown