EC is the short form of Electronic Conductivity and PPM is the short form for Parts Per Million. EC meter gives the concentration of the nutrient elements present in the solution. That quantity can be measure in both EC units and PPM. PPM is a common term as it is used to measure the impurity of drinking water at our homes. That is why people prefer to measure EC of nutrient solution also in PPM. 1 EC = EC X 500 for PPM 500 scale (U.S.A.) and 1 EC = EC X 700 for the PPM 700 Scale (U.K.).