Cannot get 0 TDS values

[workhz]

To avoid exhausting DI resin quickly you must simply put a bypass with a valve after the RO membrane.
This way, by closing the valve, you can prevent high TDS water from ever entering the DI cartridges.
By opening the valve, you can divert low TDS water into the DI cartridge, once the RO membrane has started producing water with the lowest TDS possible.

Thanks. That's the word I was looking for, bypass ... landed on flush instead .. but yeah. Bypass. I was going to automate my bypass and rodi with a simple switch but haven't gotten around to it. I use the bypass every time I make rodi now and do about 15G at a time. Significantly increased my DI life.