Question about RO/DI Units

[Dinwooj]

I have a TMC RO/DI unit installed for use on my ATO. My tap water has a TDS reading of 320 and after going through the RO/DI this gets down to roughly 45. I am aware this is too high to use still, so my 2 questions are:

1. Does anyone else have experience with this piece of equipment? Should it be producing water with a TDS of 0 meaning I have installed it wrong?
2. Solutions for this - will a de-ionizing pod make the difference and bring TDS down to 5 or less?

I have tried flushing the system etc but no luck. Weirdly the levels of reject and 'pure' water are roughly 50/50 leading me to think there is an error in the setup but cannot figure out where it is. Any help much appreciated.

 

[Montiman]

Something is definitely wrong. There are a few things to check.

What is the pressure going into the membrane? Low pressure = poor performance.

What is the TDS coming out of the membrane before the DI? A bad membrane is possible or bad DI knowing before and after the DI will help.

What TDS Meter are you using? Pen Style or inline? Pen Meters are much more susceptible to picking up dust and impurities in the air or testing container. They will almost never read 0.

 

[DE FISH]

Something is definitely wrong. There are a few things to check.

What is the pressure going into the membrane? Low pressure = poor performance.

What is the TDS coming out of the membrane before the DI? A bad membrane is possible or bad DI knowing before and after the DI will help.

What TDS Meter are you using? Pen Style or inline? Pen Meters are much more susceptible to picking up dust and impurities in the air or testing container. They will almost never read 0.

My pen always reads zero unless di or filters need replacing

 

[Montiman]

My pen always reads zero unless di or filters need replacing

You must not live in a dusty desert like me. I can't get pen meters to read below 5 ppm in most cases.