[thompsonr]

I have just bought a ro/di system which achieves the folwing tds readings
TAP 350
After passing RO membrane 18
After pssing DI resin              16

The only thing that appears wrong is that the resin cartridge is about 3/4 full.Would this cause the poor final reading.?Is there any other possible causes?
I am new to wfp and any  would be grateful for any help

[DASERVICES]

It sounds as if your resin cartridge is too small for your flow rate going through it.