"blacklights" found in pet stores, don't work for me

Hi, one of my 2 kitties is peeing on my bed sometimes. He isn't ill,
just nervous kind of guy. It's OK, I use tarp under the sheets and
wash the sheets. I want to make sure he doesn't do that elsewhere, on
carpets. So I bought the "blacklight/UV" light found in pet stores.
It does not seem to work!

After he pees on the sheets, I darken the room and use the light to
see how it works. Well, it does not - nothing shows up. Nothing
shows up when the urine is fresh. Nothing shows up when it's dried.
Nothing shows up even when it's night and everything is pitch black.
I tried 2 different brands, one of them really big, lots of
batteries. Nothing. I look really carefully and follow instructions
carefully. Make sure the batteries are new. Nothing, even when I can
see and smell the urine myself.

So of course this is never going to work on carpet or anywhere else.


What's going on? Why don't they work? Is there one urine detector
that really works? I have seen this thing AntiIckyPoo UV flashlight -
it does not use batteries, but extension cord and electricity from an
outlet, and is really expensive $70 (the lights found in pet stores
are $30 or less). Is this going to work?

Please give me recommendations. Thank you very much.

Mark Galeck