Optimal UV reactor design ensures UVC light is delivered in the most efficient manner by maximizing overall UV dosage for all parts of the fluid entering the reactor (e.g., all of the fluid needs to be uniformly exposed) for disinfection. This application note outlines how using reactor materials that offer higher reflectance of the UVC wavelengths can optimize the UV intensity and uniformity in the system to ensure target microbes are exposed to enough UV light for complete DNA inactivation.