UV Sterilizer? Opinions on if one is necessary.

[newreefer_59]

Have a 150 gallon Reef tank up and running with SPS, LPS and fish. Not much of an issue any longer with algae blooms or the like, but do find myself cleaning the glass almost daily as I am sure is fairly routine for most of us.

Anyway,is a UV Sterilizer necessary as a useful tool - in your experiences and opinions? If so, is it fine kept in the sump or can it be in the main tank.

Appreciate any responses.