Okay. I've never dealt with hard water from any rural source I've worked with, but have been to places where water is as hard as a rock. Well, almost.
Still, I've never had to mix chems with anything harder than most city tap water, so got to thinking that a good surfactant may help break it down[?].
I would say artificially softened water, but it's really just plain old salt added to it. Can salt interfere with the fert or glyphosate is the big question. It may hurt the plants. I know it makes cats sick.