the input port 145 to the germicidal filter unit 34 the connection between the pipe 140 and the germicidal filter unit 34 may be made in any conventional waterproof fashion the cover 220 of the germicidal filter unit 34 is removable for cleaning and maintenance purposes extending through a port 300 in the cover 220 of the germicidal filter unit 34 is the germicidal bulb 310 the bulb 310 is a standard 30 or 15 or 45 watt germicidal bulb well known in the art receiving electrical power through the connection 200 and a connection 315 the connection 315 is supported by a flange 320 in the base plate 230 such that the socket 315 may be removed if necessary for maintenance purposes the germicidal light 310 is about 35 inches long with a one inch diameter surrounding the germicidal lamp 310 is a protective shield 325 whose purpose is to insulate the lamp 310 from the temperature differential which may exist in the fluid flowing through the cavity 330 within the germicidal filter unit 34 the shield 325 may be left out if there is no variation between the temperature of the bulb 310 and the fluid in the cavity 330 the composition of the shield 325 is of a standard variety of a type of material which does not inhibit the passage of the ultraviolet germicidal waves the port 300 at the top plate 220 of the germicidal filter 34 and a port 335 at the base 340 of the.