I worked at a city waterworks, when I was young ... whenever I was curious about anything on those test printouts, I'd call the local water softener store, ask them specifics, 'some' of those guys knew their stuff ... in general, if you're using drinking water anywhere in the USA, your only concerns will be pH, chlorine, and calcium levels ... you can adjust the pH, no biggie ... the chlorine will evaporate overnite, faster if aerated, and calcium is usually a good thing ... calcium will buffer the nitrates in the ferts, etc ... great question, makes my brain hurt, trying to remember that stuff ... good luck :thumbsup: