product descriptionBe sure to add water according to the required ratio, otherwise it will affect the accuracy of the calibration and increase the error Calibration Powder : pH standard solid substance. It can be used after adding some water. Suitable for calibrating any type of pH meter. Each sachet can prepare a standard solution of 250 ml. Calibrate in the order of 6.86, 4, 9.18Tip: The PH probe is a glass product and it is a fragile product. Please don't bump into things. Once the damage is not replaceable, you must protect the probe. After use, use a paper towel to gently absorb the water from the probe. Open the pen cover, the number may float, this is a normal phenomenon, because the contact of the probe with the air may cause the number to floatThe pH meter has been tested. tee calibrated before delivery, the buyer does not need to recalibrate after receiving the goods In the following cases, the pH meter must be recalibrated. : 1. It was used for a long time after calibration; 2. Frequent use of special electrodes; 3. The measurement accuracy requirements are relatively high.Battery installation: If the brightness backlight decreases significantly or if the display value is blurry, the battery needs to be replaced. When replacing the battery, simply remove the battery compartment and replace it. Note the polarity. of the battery.Standard configuration: 1XPH meter 3X calibration powder 1 gift box. 1 instruction manual.