[stevecs]

UV is just short wavelength radiation which can be ionizing or not depending on frequencies that you are letting through. I was thinking about this path but the items here mentioned (about limited coverage area/hidden bacteria, and added heat issues of including this in the loop (not to menion power requirements to run it). Has anyone used or tried out low level radioactive material? (radium, polonium, et al?) Figure it would be a good fit here.