Hanna HI-711 Chlorine CheckerThe HI 711 Checker HC (Handheld Colorimeter) provides a simple, accurate and cost effective way to measure total chlorine. Chlorine is a popular disinfectant used in municipal water, fruits and vegetables, as well as equipment in the food and beverage industry. Though beneficial in destroying pathogens, levels greater than 4 parts per million (ppm) is harmful to humans and therefore, must be monitored.