Abstract: By providing a fluid flow chamber which is preferably constructed in an elongated, cylindrical shape and incorporates an elongated cylindrical sleeve in which an ultraviolet radiation producing lamp is positioned along the central axis thereof, with the outer surface of the sleeve covered with a unique coating layer, a highly efficient and low cost fluid purification system has been achieved which employs ultraviolet radiation. The unique coating material of the present invention allows the ultraviolet radiation to pass therethrough substantially unimpeded, while also virtually eliminating any buildup of light blocking deposits from the fluid on the surface thereof. As a result, the purification system of the present invention is capable of providing the desired high radiation level exposures for substantially extended periods of time without requiring repeated maintenance.