[sick472]

Here in central Missouri, a 50/50 mix is the ticket. I buy the concentrate and pour half in an older empty bottle...add water, mark the bottles with the word "mix'd" and carry on. I use well water that has some hardness, but not much. Some well water would be too hard IMO and store bought filtered or distilled would be much better.

Under an emergency situation where you too lazy to go to the store...an occasional adding of harder well water isn't going to take the truck down, but I would not make a habit of filling a system that has that slow unknown leak regularly with a hard water mix.