I run a close loop with a UV, Mechanical, and fluid bed filters by coral life and a second with a 45 g refug, and 20 gal in tank overflow with bio balls. Now as the UV I have never had any sick fish in the main tank. BUT I only run it because it was just one more thing that might help. Many say it is not worth it. Other live by them, I have to say if you got the $$ do it, but if not just QT your fish better and you will never need a UV. I also run a Vortec XL once a week in the sump for 8 hours after I do a little clean up. It realy helps with keeping my tank super clean. I have messy fish. Others use this new eco tube you put in line " You never have to do a water change again" or so they claim!!! But there is no one product that will clean the tank, kill ich and cure your fish. Good house keeping, water changes, checking your water once or twice a week and a major every two week or less a good QT tank will make all these products worthless.
Some times the old ways are the best ways. JMO
