It is necessary to calibrate PH meters and suggested that this is done on a weekly basis.
Use the essentials buffer 4 solution to calibrate PH meters. For successful and accurate calibration insure the solution is at room temperature.
Essentials pH buffers are a known solution of a certain pH value, in this case the value is 4, designed to test the accuracy of pH meters used to measure the pH of a nutrient solution. Use to Calibrate your EC/CF meter every week to ensure maximum accuracy. Features CRC Cap for Safety.