On Oct 24, 11:19*am, "Stormin Mormon"
wrote:
The radioactive isotope goes flat after a while. Normal
decay, you know.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Tony Hwang" wrote in message

...

ransley wrote:

Just curious, why replace them, they still work right.

Hmm,
Not after 20 years!!! Would you trust that old detector?

Decay of isotope, isnt that for Co detectors? Who says 20 years, the
Manufacturers of course. I have heard of no independant saying 20
years.