RO water would no doubt be a good thing to have but as long as PPM out of tap isn't out of site and people can actually drink it without growing extra body parts then tap should do you fine. In my opinion anything under 200ppm is usable. Mine runs around 120/130 and I raise it to 200 with calmag before adding anything else. As long as I can do what I have been doing with tap I'll stay with it, to me RO seems to be a pain and takes to long but if my water was up around 600 I would no doubt be singing a different tune :wtf: