M1: Chlorides (mg/L) Conductivity at 20ºC (µS/cm) Fluorides (mg/L) Phosphates (mg/L as phosphate ion) Total phosphorus (mg/L P) Nitrates (mg/L) Nitrites (mg/L) pH (pH units) Potassium (mg/L) Sodium (mg/L) Sulfates (mg/L SO4)