pH Buffer 7 is will calibrate your pH meter, making sure that you get the most accurate reading.
Using pH Buffer 7 is simple:
Pour some of the pH Buffer 7 into a small clean vessel
Immerse the probe of the meter into the buffer.
Leave the meter for a few minutes then push the calibration button on the meter to set it to 7.0.
Your pH meter is now calibrated and ready to use again