Hi All, My water coming out the tap is at 100 on the TDS I've got a 25L DI and using it to fill up my Trolly system at the minute!! Am about to buy a Van system but am not sure if I should get a RO?? Is it going to cost me lots more money without one?? Obversely it depends on how much water I use!! I don't like the sound of using an RO and throwing lots of water down the drain every night. I have seen I video on you tube of people using two DI vessels?