Digital PH Tester Pen 0.01Hi-Accuracy For Water Quality Test Hydroponic Test Features: 1. Ensures that your pool, regular hydroponics pH or even drinking water has a perfect pH balance and is safe to use with the Precision pH Tester. 2. Features a sensitive electrode sensor for accurate pH readings. The detailed manual included will show you how to get the best possible accurate and stable readings. 3. Temperature compensated, the standard measurement of the instrument is 25 degrees, when the solution temperature is higher or lower than 25 degrees, it can be automatically corrected to reduce the error and improve the accuracy. 4. Ideal test tool for home and laboratory use. Ideal for testing water, swimming pools, aquariums, spas, hydroponics, food, wine and beer brewing, and more. 5.The pH meter has an auto-calibration feature that adjusts for water temperature and quality, and simply waits a few seconds during the test to get a pH reading. Operation Tips: 1.5 minutes without operation, the meter will automatically shut down to extend the battery life. 2.The height of the pen end immersed in the solution should be less than 4cm Calibration Methods: 1. Turn on the switch and make sure your instrument is in working condition. 2. One-point calibration: put the instrument into 6.86 solution, press and hold the "CAL" button for 5S and then let go, wait for the screen to finish flashing to complete the calibration. 3. Two-point calibration: put it into 4.01 solution, long press "CAL" key for 5S and then let go. Press the "CAL" key again and put it into 4.01 calibration mode. Wait for the screen to finish flashing to complete the calibration. 4. Three-point calibration: Put it into 9.18 solution, long press "CAL" key for 5S and then let go. Press the "CAL" key twice to enter the 9.18 calibration mode. Wait for the screen to finish flashing to complete the calibration. How to determine that the instrument needs calibration: 1. The instrument has been used or left for a long time after calibration 2. The electrodes are used especially frequently 3. Measurement accuracy requirements are particularly high 4. Do not press the "calibration button" for a long time, otherwise the instrument needs to be recalibrated Package Includes: 1*PH test pen 1*Instruction manual 1*Storage box 3*Calibration powder Note: 1. Please allow 1-3 mm error due to manual measurement. Please make sure you don't mind before ordering. 2. Please allow 1-3g weight error. Please make sure you don't mind before ordering. 3. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you!