Also, note that the diagram that Kstatefan posted is for replacing your current unit with the 200gpd unit. It would have to be setup that way because it is not recommended to drink RODI water. The DI material is not food grade so is not recommended for human consumption.So when the DI is exhausted u have to replace the filter in it? Cause the proline I have is just an RO system and I would need to get a DI for it. I will try the TDS and see how it goes from there. Thanks for the help!