Chlorine would be your best ... Published November 23, 2016 16:53 by Terry Hughes CWS, CI, UV-CI, Problem Water and Technical Service Specialist at Culligan of Denver, a div. of Halls Water Chlorine would be your best bet, as it would also act as an Anti-Bacterial. UV would not be as good due to filming on the Quartz Tube which would then block the UV rays.