Athosanswered grow question 4 years ago I have one of those EC / PPM meters, they are fairly easy to use. Your reading of 1200 is in uS/cm, which is the same as 1.2 mS/cm or if you convert it into PPM 600. Hope that clarifies it for you. Most info around has the EC in mS/cm, just divide your reading by 1.000