Here is my article about whether or not to use a UV Sterilizer:
I would also point out that even if you purchase a decent UV Sterilizer, to not change your UV lamp regularly [6 months best], your UV Sterilizer will become a useless device.
What is also worthy of note is that so many sellers both online and at places such as Lowes now often sell cold cathode and medium pressure UV Replacement lamps which have an output of less than 1/3 of the important UVC wavelengths necessary to effectively operate your UV, so buyer beware!
Ref:
G