One of the first things I bought in this hobby was an RO/DI system. How can we be guarenteed that our tap water is always within the correct parameters for our tanks? For me I like to start with pure water, that way if it ever gets messed up I have no one to blame but myself One more potential issue eliminated in my mind.
**ERIC - our water tests out at 31, at least mine does and I'm only a few miles down farmington road from you, so it is pretty low here.