pH Test with Hach Sension1 and Orion 250A+

Note:  Instruments are calibrated before each use.

Calibration

1.  Press ON/OFF button to turn on.

2.  Using three small white plastic cups, pour each buffer solution (4.01, 7.0, and 10.0) into its own cup.  Also fill a cup with DI water to rinse the electrode.

3.  Press the cal  button. Dip electrode .5-1 inch into 4.01 buffer solution.

 When 1? appears in the upper right corner, press the READ/enter button.  The meter will beep three times when it has stabilized.  If the meter does not read 4.0, the reading can be adjusted to the correct measure by pressing the up and down arrows.  When a number is changed, press READ/enter to move to the next number.

4.  Remove the electrode from the buffer solution, rinse with DI water, and place in the 7.0 buffer.  When 2? appears in the upper right corner,  press the READ/enter button.  The meter will beep three times when it has stabilized.  Repeat this process for the 10.0 buffer solution when 3? appears on the screen.

5.  When complete, press READ/enter to approve the slope and begin measurement.

Measurement

1.  Press ON/OFF button to turn on.

2.  Place the cup on a stir plate, place a stir bar into the cup, and turn the stir plate on so that the sample is gently stirred.  Dip the sensor .5-1 inch into the sample (make sure it is submerged) and let meter stabilize.  Make sure the meter is reading pH values by pressing the pH mV button.

3.  Record the pH reading when the meter has stabilized. 

4.  Rinse electrode with deionized water before testing next sample and before turning off

for storage.  When measurement is complete, put

the liquid filled container backon the electrode for

storage and give the sampleto the turbidity station.