it really all depends on your tank. Some feel that a uv sterlizer is a NEED to have, while others feel that its a nice to have but not a need, correct me if im wrong but uv sterlizers put out ozone which from what i think is not good for corals. for what purpose will you be useing it, if its to control parasites then i think that its okay to have but not on all the time, some feel that if you have a uv on itll prevent parasites 24 hours a day, but others also feel that if your fish have a dependancy on a uv that there immune system will deminish . if its to control unwated algae theres better ways of doing that(like a ro/di unit)