Laboratory Testing Measuring Equipment PHep Portable pH/mV Meter HI8424 PH METER HI 2211-02 / HI 2210-02 Dissolved Oxygen Meter HI9147 Edge® Multiparameter pH Meter HI2020-01 Dissolved Oxygen Meter Lutron DO-5509 Benchtop pH meter BP3001 Dissolved Oxygen Meter Lutron PDO-519