pH Calibration and Testing Made Easy with the Hanna pH Checker Plus - BRStv How-To
Calibrating the pH Checker Plus only takes a minute and you can choose if you want to calibrate between 4.0 and 7.0, or 7.0 and 10.0. We highly suggest calibrating any pH probe to the range that it will be reading. For most reef tanks, you will want to use 7.0 and 10.0 set points, and for calcium reactors and most freshwater aquariums, the lower threshold would be ideal.
A couple of tips when calibrating the Hanna pH Checker Plus is always to use new calibration solutions, and to rinse the probe end in RODI or distilled water between sachets. We like to calibrate our probes once every one to three months depending on how often we are using the particular probe.