What can cause the APA6000 Hardness Analyzer to read high?
High readings on the APA6000 Hardness Analyzer.
Addition of reagents changes the sample matrix. In case of a saturated solution full of contaminants, this can become supersaturated when mixed with the reagents, resulting in contaminants falling out of solution. Even after the event, the contaminants left behind can then re-dissolve in the new incoming sample, resulting in high readings. Reagents and sample in the APA6000 are never mixed UNTIL they go into the MIXER module, and this is where the contamination is left behind. It then contaminates all subsequent samples until it eventually wears away. An acid cleaning of the mixing chamber may resolve the issue.