Frequent calibration is the best habit to maintain the measurement accuracy of the pH sensor/controller, because calibration can make your readings accurate and reliable. All sensors are based on slope and offset (Nernst equation). However, all sensors will change as the age. The pH calibration solution can also alert you if the sensor is damaged and needs to be replaced. The standard pH calibration solutions have an accuracy of +/- 0.01 pH at 25°C (77°F). Sinomeasure can provide the most popular and commonly used buffers (4.00, 7.00, 10.00 and 4.00, 6.86, 9.18) and which are dyed different colors so they can be easily identified when you are busy working. Sinomeasure standard pH calibration solution is suitable for almost any application and most pH measuring instruments. Whether you are using various types of Sinomeasure pH controllers and sensors, or using a benchtop pH meter in a laboratory environment of other brands, or a handheld pH meter, pH buffers may be suitable for you. Noted: If you are measuring pH in a sample that is out of the 25°C (77°F) accuracy range, refer to the chart on the side of the packaging for the actual pH range for that temperature.