I recently had my water tested for TDS and straight out the tap my city water read 046ppm and my RO water read 016ppm. Two part question first how many of you would use this water straight out of the tap just the way it is? Second shouldn't I get 000ppm after going through the filter? I bought this RO filter used should I just invest in a new RO/DI? Please help me out with these questions.