The FCL’s precise amperometric sensor measures free chlorine in real time and is available in three different measurement ranges: 0-2ppm, 0-5ppm and 0-10ppm. The sensor’s long-life design reduces maintenance cycles, which lowers lifecycle costs with less frequent sensor membrane cap/solution replacement and reduced technician installation time. After hypochlorous acid (HOCl) diffuses through the FCL sensor’s membrane, it is electrochemically reduced, releasing electrons and creating a current flow proportional to the free chlorine concentration in the medium outside the sensor. The low current output is then conditioned to a 4-20mA direct output. The FCL’s sensor operates in a range of 4-11 pH, a temperature range of 0-45°C (32-113°F) and at a maximum pressure of 14.7 psig (1 Bar).