The most common reasons for pH meter error is dry storage of the electrode and electrode contamination. These cause loss of accuracy, reduced performance and slower response times.

Avoid placing pH electrodes in harsh chemicals especially those of high concentration or extreme pH e.g. pH Up.  These can damage electrodes or increase the need for electrode maintenance.

Thoroughly clean the electrode after use and always store your pH meter with the cap firmly in place.

Frequency of meter calibration is crucial and will optimize your pH meter’s performance.

Calibration Solution pH 7.0

For calibration of pH Meters at pH 7.0
pH Buffer 7.0 @ 25° C  (77° F)
Based on international (APHA) standard formula

Calibration Solution pH 4.0

For calibration of pH Meters at pH 4.0
pH Buffer 4.0 @ 25° C  (77° F)
Based on international (APHA) standard formula

Calibration Solution 2.76mS

Conductivity Meter electrodes invariably become coated with inorganic or organic impurities. This causes a loss of accuracy.

Conductivity (cF, mS) or TDS measurements are used to gauge the total concentration of all salts (i.e. both beneficial and toxic) present in the nutrient solution. They cannot provide any detail on the concentrations of individual nutrients.

Therefore, since a ‘satisfactory’ reading does not imply a balanced nutrient mixture (or provide information on the level of nuisance salts), it is wise to dump every 7-14 days. This is particularly necessary when using salty make-up water because such water causes nuisance chemicals to build up rapidly to toxic levels.

For Calibration of Conductivity (EC) and TDS Meters
Calibrates to 2.76mS/cm or cF 27.6 at 25oC (77oF)
Contains Potassium Chloride
Based on international (APHA) standard formula


Available in 1L, 500ml & 250ml