HI 22091 pH/mV Meter with Manual Temperature Compensation (MTC) and Analog Output The HI 22091 pH/mV Meter with Manual Temperature Compensation (MTC) and Analog Output provides a simple to use, cost effective method of measuring pH.  The HI 22091 replaces PH 209R and features a large, easy to read LCD, built-in solution holders and an attractive redesigned case. In order to achieve maximum ... Read More »