RODI not doing what it's supposed to!

[Ryanerickson]

I had a issue like this it ended up I had had di balls that was exhausted in my last pre filter but I figured it out by putting the line coming from tap directly into the ro then tested water that came out it was 0. What is the problem with di balls before ro? Will it make the life of my ro membrane shorter? I thought it would help it last longer because water coming out of pre filter is coming out at 1 ppm then it goes into ro any one know ? Thanks

[11purewater]

The DI is there to filter the Ro product water to 0 TDS(non conductive) if you can't achieve it with the RO membrane alone.For example 200 TDS feed water going through a membrane @ 98% rejection=4PPM product water,DI after brings it to Zero.

[hillegom]

Originally Posted by 11purewater

The DI is there to filter the Ro product water to 0 TDS(non conductive) if you can't achieve it with the RO membrane alone.For example 200 TDS feed water going through a membrane @ 98% rejection=4PPM product water,DI after brings it to Zero.

I agree. The DI is the most expensive, and it should be last. You try to get the lowest TDS out of your system that you can and then send it to the DI where it will come out at 0 TDS.
If after the DI, it is not 0 then the DI is exhausted and you need to replace it.