Most of the pH meters work in the same way but you should always check what your manual says. A general overview of the calibration procedure is present here. Place the instrument into calibration mode either by pressing the CAL button or pressing and holding down the ON/OFF button until CAL appears on the screen.
At this point most meters will request the use of Buffer 7.01, and all meters will need to be calibrated to pH 7 buffer first.
Place the electrode in to the buffer 7 solution so that the bottom inch of the electrode is submersed. pH meters (some meters) are programmed to automatically recognise a selection of Buffers (please check the product specific specifications to find out which solutions). While the meter is waiting for the reading to stabilise a clock symbol or hour glass symbol will flash (on some of the hand held meters the reading will flash). If the meter is unable to recognise the Buffer the message WRONG will appear on the screen.
Once the meter has reached a stable reading it will automatically calibrate itself. The meter will then request the use of the next buffer solution, the screen will now show ‘USE 4.01’.
At this point remove the electrode from the Buffer 7 solution and rinse it under tap water (or deionized water) and then place the electrode into the Buffer 4 solution.
Once again the meter will show that the reading is stabilizing by either flashing or showing an hour glass/ clock symbol.
Note : Procedure / symbols/ steps will change from vendor to vendor