I believe in UV sterilizers and use them on all my tanks. However, keep in mind that this has been debated by so many people that the review is rather mixed.
UV lights split the DNA of the parasites, thus prevent the continual population of things like ich.
The big key is that the flow rate of your powerhead must be low enough so the water has adequate time to be exposed to the light. Some UVs have dead spots, and some like the TurboTwist make the dead spot issue a non-issue. In using both the TurboTwist and a couple other brands I have found that I actually prefer the TurboTwist due to the logic of the water having three times the exposure to light rate provided of course, you use the correct powerhead for the light.
Of course, I also believe in the use of a garlic soak for all frozen or fresh food as well.
There are reasons ScubaDoo has given as to why he doesn't use them and some of his arguments are rather compelling reasons, but for me personally I like the added peace of mind.
I respect SubaDoo highly for his knowledge and our debate could have been construed as somewhat spirited at times by people just reading the boards however I believe he has a lot of knowledge to share with everyone... including me. He gave me compelling reasons to re-think the UV lights, but in the end I decided that peace of mind outweighed the extra expenses involved in electricity and light replacement was worth it for me.
Denise M.