Adding a UV sterilizer to a reef tank sometimes does more harm than good. It not only kills the bad but also kills the good as well. Incidentaly it does not wipe out everything. It only kills what passes in front of the light. If a fish still has ich on it, or a bacteria infection, it wont kill it unless the bacteria or ich on the fish passes the light. That also depends on whether to correct flow through the unit is met. They are most beneficial if the bulbs are clean and changed out regularly. For the most part it is unnecessary on a reef tank but very useful in a FISH only tank. I would keep it with the freshwater setup or a fish only tank.