Showoff. I have no "mu" symbol on my Walmart keyboard.

Thassa micro-siemen. It is a measure of conductivity. Siemens are the reciprocals of ohms. They are also what make my pants crunchy. :thumbsup:

Electrical conductivity (EC) is what a "TDS meter" is actually reading.

Your "ppm" is then estimated using a conversion factor of your meter manufacturer's choosing. So, while a ppm reading may vary according to the conversion algorithm, EC is "constant."

International discussions are often in EC terms to avoid the skewing caused by different conversion factors.

Don't know if you need it or not. But if you're not gonna use that "mu" character...