kills algae with relatively small 'doses' - however killing parasites requires much larger 'doses'. Basic guesswork would say that your UV
unit was designed to kill algae at a flow rate of about 300-500gph based on the manufacturer's tank size specs. Wild guesswork would indicate a flow rate of 100-150gph or so would be necessary to extend the exposure time of the water inside your UV
unit sufficiently to do the job on parasites.