I've had a 29 gallon BioCube for almost 5 months now. I'm not sure if I've just been bit by the Black Friday shopping bug...or if I really do need one of these: (opinions and advice are very very welcome!)
Oceanic Biocube Mini Ultraviolet Sterilizer
No, you don't need it. I really don't like them. Yes, they kill pests, but they also kill all the good stuff like beneficial bacteria and various types of pods. And... they're not too effective in killing the bad stuff IMO.