What does PPM stand for? on the back of the advanced nutrients

[Mississippi Steve]

Parts per million (PPM), and Electrical Conductivity (EC), both the same thing, two different units of measurement.

Americans tend to use PPM more often, and europeans use EC more often.

You need a TDS electronic pen reader (Total dissolved salts) which tell you the PPM (parts per million) of the TDS of the water.

This is how you know how strong your nutrient strength is.

Roughly 500ppm equals 1 EC. therefore, 300ppm equals .6 EC, 250ppm equals .5 EC.

tap water is normally about 300ppm, when you add nutrients- obviously the ppm will raise.

The tendancy of using PPM comes from industry standards. If you pull out a NIOSH pocket guide, or any MSDS, most all of the measurements (including IDLH, and weighted averages) are expressed in PPM.