If you go to the auction website, there are a couple dealers in SoCal that sell countertop ro/di units for $50. I have used them for a couple years now and have measured 0 for everything, including tds and heavy metals. The guy I bought from last time sent me 6 2000 gallon membrane/filters for $80 including shipping. With good, no-install filters so inexpensive, why not buy your own?