Hayward HCC 4000 HCC4000WIFIAU pH / ORP WiFi Controller with Gold ORP Sensor. The HCC 4000 Series water chemistry controllers monitor pH and Oxidation Reduction Potential (ORP) while automatically making chemical feed decisions to ensure safe levels and destroy harmful pathogens. This controller can calculate derived free chlorine and display PPM. The HCC 4000 controllers also feature customizable chemical feed options allowing the user to fine tune the amount of time and frequency the controller engages chemical feed for more consistent pH and sanitization levels.