The HI96735 Total Hardness EPA Portable Photometer combines accuracy and ease of use in an ergonomic, portable design. Using the HI93735-0 ready made reagents a user can accurately determine the total hardness concentration in samples within a low, medium, and high range. The low range measures from 0 to 250 mg/L CaCO3, the medium range measures from 200 to 500 mg/L CaCO3, and the high range measures from 400 to 750 mg/L CaCO3. Users can simply choose the appropriate range depending on their expected sample concentration. The HI96735 offers many advanced features including the exclusive CAL Check™ function used for performance verification and calibration of the meter.