Difference in TDS Readings

[Powersds]

On my RODI system the outgoing in line TDS always measured 0, but it currently is 3 but a handheld TDS UNIT measures 0. Why would this be. I thought I needed to change the filters so I did (it was getting close to a change anyway) but the TDS readings stayed the same.

 

[vetteguy53081]

On my RODI system the outgoing in line TDS always measured 0, but it currently is 3 but a handheld TDS UNIT measures 0. Why would this be. I thought I needed to change the filters so I did (it was getting close to a change anyway) but the TDS readings stayed the same.

Try flushing the unit and retest