I bought a new UV lamp for a pond filter but I don't see any light from the inspection lens in the lamp holder. I checked the the connection in the socket and I see 240v. Does that mean the ballast is working? I've been reading as much as I can but I'm still not sure.
Does this kind of lamp with no phosphor produce no visible light and therefore the lens at the end of the clarifier tube must have something to make the light visible? Is there any other way to test the lamp?