There’s different scales for PPM.
“
There are many different scales used for different industries around the world and for many different reasons! Did you even know there are more than two scales? The most widely used scales in Hydroponics are the 500 scale, 650 scale and the 700 scale.
What's the difference? The ppm 700 scale is based on measuring the KCl or potassium chloride content of a solution. The PPM 500 is based on measuring the NaCl or sodium chloride content of a solution and is also referred to as TDS - total dissolved solids. Individual nutrient ions have different electrical effects!”
Just use EC, not confusing.......kapish
View attachment 4470398