IMO you may not see a difference. UV's are not extremly guaranteed to kill free floating ick. If this is what your using it for. Iv had one running for over a year and I still contracted ick in the tank. But this was before I knew much about QT and hypo to cure ick.
Thebest solution for killing ick is hyposalinity. Hypo has to be done in a QT because hypo will kill inverts, corals and LR. Its droping the salinity to 1.009 over a few days time. Ick can not survive in this and its less stressful on fish. While your thinking of it set up the QT.
Read your manual for the UV...it will give you recommended flow rates to accomplish certain tasks...
Research on treatment of ick itself...there are as many remedies as there are opinions on this board.
There is no "best way" to treat and cure ick. There are many here whom feel the hypo is the way to go...but they often times forget it is a simple opinion...