When you say 0 TDS tell the whole story. You are deceiving new buyers. Tell them the raw water TDS, post RO TDS and RO/DI TDS and how long your DI lasts until you see a reading of 3 TDS.
I can get 0 TDS with a little bowl filled with DI resin, for a short time anyway.
The difference in filter quality and life of the DI resin is tremendous between the Typhoon III and a Filter Direct unit. There really is no comparison.