One other thing!!! If you DO get and use a full RODI system, you will need to buy a mineral ion liquid to dose your water with. Either manually or with an additional filter stage.

Water completely lacking in minerals or extremely deficient has its own potential for health risks. Most notably high potassium loss diuresis and sudden onset hypokalemia from that.

The following is a good way to do it if you wanna go the manual route:

http://www.traceminerals.com/products/liquid-tablet-minerals/concentrace-ionic-minerals

You can buy the liquid from Swanson's rebranded for less than you can the Trace Minerals Research brand btw.