Can you tell if a Powersun bulb has been used?

[Escalade]

I got a 100 watt powersun off ebay, and when I opened it, it didn't look new (was listed as new). There was what seems to be water stains on the bulb along with some dust.

Is there anyway to tell if its been on for extended periods of time? I don't want to use it on my cham if its been in use for a while and has low uvb power.

it was listed for $13 and the ebay seller has over 2 thousand positive feedback and also owns a petstore but I'm still a little skeptical

 

[Escalade]

anyone? also towards the threads its blackish color(not sure if that means anything)

 

[Olimpia]

If you had a UV meter (or could borrow one from someone) you could compare its output to a new bulb (there have to be readings online here somewhere) but otherwise I don't think you can. I can't think of any other way to tell for sure.

 

[ataraxia]

how to tell if a powersun has been used......this is very tricky. you must round up three frogs feet, two leaves from a ponnanja plant, a lock of witches hair and...well thats about it. then you take all of it and just throw it all away (like money). then you buy a bulb from a source you can trust

water stains + dust = used.