Couple silly questions: Can a DI vessel be used as sediment filter? (with used resin obviously) Basically what do you do with resin more than ~10ppm, if RO produces water less than that? If water before DI is 0ppm will used resin make it worse? I know daft question. Does RO outlet (pure) have to be physically higher then the tank water goes into? Will it damage the membrane if water has to be 'pushed' upwards? Will it slow down the process?