so I read the sticky and I need someone to let me know in plain English LOL ... my ppm meter has uS , mS , .5 , .7 and EC on it.... wht should I be using to calculate my ppm’s?? Thanks!!!
EC (Electrical Conductivity) is what those meters measure. Multiply EC by 500 to get ppm that is used in the US. Some other countries multiply by 700. My guess is that the 0.5 setting will get you the x500 ppm.