Buffer solution pH 4 for calibrating a pH meter; regular calibration of a pH meter ensures reliability.

• Suitable for all common pH meters
• Convenient spout
• pH value: 4
• Contents: 500 ml
• Including measuring cup

• The electronics in a pH meter must 'understand' the signal emitted by the pH electrode; this signal can fade as a result of ageing, poisoning or contamination. This is why a pH meter needs to be calibrated, and this can be done with a fixed value buffer solution
• It is advisable to clean the electrodes first so that the deposits are removed
• Do not reuse the buffer liquid, there is a risk of contamination
• Make sure that all electrodes touch the liquid

Normally a pH calibration starts at pH 7; a liquid with a pH value of 7 is called neutral and this is the zero point of the measurement. A second measurement can be used to determine the slope used to calibrate the pH meter and thus ensure that subsequent measurements are reliable. In the base region this is pH 9, in the acid region this will be pH 4

• pH value: 4
• Contents: 500 ml