I like them. Most people think they kill plankton and other things in a reef tank. I have viewed tanks that run them and tanks that do not. There was really no difference in the sandbed fauna on either tank or the growth of other liverock critters. The tanks that ran UV
'S had much clearer water though. On my current 240gallon tank that is in the works i will run a UV
. For a smaller tank the Coralife turbo twist UV
'S work great!