Hi Karen, Your going to drive yourself crazy if read what everyone thinks about water. I speak from experience. When it's all said and done, the best thing to do is use distilled water or RO.(Or move to the rain forest your plants came from

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If your current water system is introducing salts into the water your using for your plants, STOP using it. Can you tap into your supply before the water gets through the softener? If so, you should be ok as long as you flush with plain water monthly. The salts will build up to toxic concentrations for your plants over a period of time.
Firstrays.com has a great and simple explanation of water quality, if haven't read it already.
I'm in the Northeast (upstate NY) and I use well water (un-treated)and MSU fertilizer for well water and my 'chids do ok.
Good luck, Bill