yes on all large tanks
the thing about UV sterilizers is that you don't really need one...until you really need one...but of course by then it is usually too late because you didn't have one installed.
Oh yes I run one now. Since I moved into my new place, we have had a water softner. My water has been cloudy ever since. It has drove me absolutely CRAZY!!!!No matter how much water I changed, next day cloudy again! Two days ago I put on a pond filter with a 19W UV bulb built in. Two days later, the water is crystal clear
. Placed it between my return pump and the tank, works great!