Pure water in loop has a higher conductivity


As in title, I would like to ask about the reason of higher conductivity of pure water in loop. After EDI device the conductivity is about 0.1 uS/cm, but in loop there is about 0.6uS/cm. The max value is 1.3 uS/cm in temp 25C, so there is no problem. In the other installation we have the similar situation, the conductivity is more or less 0.5 uS/cm higher in loop than just after EDI. In the third system there is the other manufacturer of pure water production device, but the same difference between conductivities. I need to add that in the first system there is no CO2 absorption bed before sterile filter so I thought that is the reason, but in the others installations we have the bed ( and it does not need exchange yet).

I have searched the reason in Net and guidlines and I found nothing clear.

Have You some idea why the water’s conductivity in the loop is regulary higher than after the EDI system ? Or maybe You just can say values of conductivity in your systems ?

I know my is english is weak, forgive me mistakes…

Best regards

I know the problem is not so easy, so maybe u just can put some (historical) values of your pw system ? I would like to know is the regular difference betwen post EDI and loop water conductivity.