Leave pH probe to soak in salt water in your glass beaker for at least 30 minutes. Then please do as follows:
Heat the pH 4.01 and pH 7.01 solution to 25.0 Celsius.
Place the probe into the pH 4.01 solution. Leave it there for at least 5 minutes.
Start calibration procedure for pH 4 solution.
After 5 minutes, rinse in RO water, pat dry.
Place into pH 7.01 solution. Leave it there for at least 5 minutes.
Start calibration procedure for pH 7 solution.
Complete the calibration.
After calibration please test accuracy.
Leave pH probe for 5 minutes in pH 4.01 solution and test accuracy. The difference shouldn’t be higher than 0.05.
Then leave the pH probe in pH 7.01 solution for 5 minutes to check the pH probe is accurate to the measurement solution. The difference shouldn’t be higher than 0.05.
Here is the video about the calibration:
Regards
Reef Factory Team