Greisinger gmh 3530 precision instrument for measuring ph orp and temperature greisinger gmh 3530 p the greisinger gmh 3530 is a precision instrument for measuring ph orp and temperature the optional measuring electrodes are equipped with a bnc or mini din connector and can be changed easily p p the gmh 3530 is a simple ph mv mvh rh and deg c hand held instrument depending on the electrode used the measuring data can be shown and read on the lc display of the ph meter p p add