if using Reverse-Osmosis water, you need to add Cal-Mag+, to replace the missing calcium and magnesium (usually about 10ml per gallon) ... you'll also remove other critical minerals, (a good reason for me to stop using my RO water) ... I would look for a nice source, like a local spring, creek, etc., (but their pH may vary from day-to-day), or work with your present tapwater ... chlorine is usually the only major negative, regarding tapwater, but it evaporates overnite, especially if you can aerate it, with a bubbler ... chlorine doesn't hurt plants, but it kills the beneficial organisms in the soil, or hydro solution ... good luck :thumbsup: