To calibrate your HOBO MX pH and Temperature Logger MX2501, follow these steps: First, gather your supplies, which include deionized or distilled water, a squirt bottle, calibration solutions of pH 4.01, 7.00, and 10.00, and the logger with the pH electrode. Next, replace the clear storage cap on the logger with a closure cap. Open the HOBOconnect app on your mobile device or computer and connect to your logger. Once connected, tap on the logger tile in the app. If prompted, initiate the calibration process by tapping "Calibrate". Rinse the pH sensor with deionized or distilled water using the squirt bottle. Submerge the sensor end of the logger in the pH 7 solution and tap "Start". Ensure the sensor end cap, temperature sensor, and closure cap are submerged. After the pH reading stabilizes, tap "Confirm". Rinse the pH sensor again with deionized or distilled water. If using the pH 4 buffer, place the sensor end in the pH 4 solution and tap "Start"; otherwise, tap "Skip" and proceed. Once the pH reading is stable, tap "Confirm". Rinse the sensor with deionized or distilled water. If you're using the pH 10 buffer, place the sensor end in the pH 10 solution and tap "Start". After the reading stabilizes, tap "Confirm"; otherwise, tap "Skip". Verify that the slope and offset values are acceptable and then tap "Save". If the values are not acceptable, go back and repeat the calibration. Finally, rinse the pH sensor with deionized or distilled water. If you're not deploying the logger immediately, store the pH electrode in storage solution. Unscrew the sensor end cap and fill the clear storage cap with storage solution to the marked fill line and carefully reattach it to the logger. Remember to only use storage solution in the clear cap, and never use water. Do not use the copper guard when storing the pH electrode in storage solution. Keeping the pH sensor in storage solution when not calibrating or using it in water is crucial, as the hydration layer can degrade within 10 minutes if not submerged. For detailed instructions, consult the HOBO MX pH and Temperature Logger MX2501 Instruction Manual.
