Water Quality and Glyphosate Effectiveness
Glyphosate products are mixed with water for spraying,
 but if the water is ‘hard water’,
 meaning it contains large amounts of dissolved salts,
 high levels of

 calcium (Ca), magnesium (Mg), sodium (Na), or iron (Fe),
then the effectiveness of glyphosate may be reduced,
 particularly if the dissolved salts in the water are
 calcium and magnesium salts.