If there is an e +/-x next to the result on the HQd display, what does that mean?
Exponential notation on HQd.
On some IntelliCAL™ probes, results may need to be displayed in exponential notation. Only 4 digits can be displayed on the screen at one time. If there are more than 4 digits required to display the complete number, exponential notation is used. This goes both ways. If the result is 12345 mg/L and the significant digits is set to 4, the result would be displayed as 1.234 e+4 mg/L. If the result is 0.0054321 and the significant digits is set to 4, the result would be displayed 5.432 e-3 mg/L.