blacklight for actinic?

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dorian965

Aquarium Advice Freak
Joined
Sep 6, 2005
Messages
347
Location
georgia
i have a buddy that was planing on using a shop light from walmart on his tank and was using a blacklight for actinic replacement. i didnt think that this would work but could not explain why.what would be the problem with this and if no prob. then would there be any beneficial properties.
 
Fluorescent bulbs are coated with a powder called phosphors. The "black lights" do not have these. Instead they have a purple colored glass.

The idea in a regular fluorescent bulb there is usually Mercury vapor that emits UV light when in a high energy state. The UV light emitted is absorbed by the phosphor coating on the inside of the glass. The electrons in the phosphors begin to tap dance around the atoms and re-emit light in the visible wavelengths. The wavelengths emitted depend on the phosphors used. The UV really does not make it through the bulb.

Your friends blacklight does not have these phosphors and therefore is emitting in the purple visible spectrum ( a little bit), but mostly in the UV range, which you cannot see. Most blacklights emit in the UVA range which is the least energetic of the UV range.

Will it be the same as Actinic light - no.
Will it harm the critters - possibly.
Will it be beneficial - I doubt it.

Hope this helps you to explain it to your buddy.

JG
 
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