I just ran some tests and my well water is 57 ppm and pH of 7.0. Tested some melted snow also, that came in at 200ppm and a pH of 7.4. (Acid rain?) Assuming I bring everything down to a low 6 pH would you use the well water, the melted snow or distilled or RO water?
200 PPM for snow?!
That's interesting.... or frightening depending in how you look at it. "Chemtrails" is a word worth googling. I would avoid using it in the mean time.
If your faucet water is coming out at only 57 PPM consider yourself blessed my friend, you have AWESOME tap water which will work like a charm. That is unless your municipal supply uses chloramine (a more and more popular choice these days.) You can find that out by either looking up your latest water quality statement or by buying a chlorine test at the local pet store. If you need the statement, most providers will post them for easy reference of their website. If you get the test, bubble the water on an airstone for 24 hours, if the test still comes back positive, you've got chloramine. Let me make note this is not the same as chlorine, which will off-gas. Chlora-MINE is stuck in your water. You must use a carbon filter to remove it.
You said it's coming from a well, so you should be good either way.
A small boy filter would be the most you will ever need, and then I would only buy it if I intended on running hydro. Soil growers can have the luxury of not having to work with 0 PPM to start. Just PH it to the proper range and you will be good.
One last thing... at a waste/supply ratio of 3:1 or more, RO will simply be a waste. Save your money and the gallons. I wish I had water as good you you!