[george renwick]

Hi i am using double di and theres something not right with it which i canny put my finger on it .
Going through two di,s it comes out at 2ppm ! 
Now if i test the first di by itself it reads 2 ppm so its pulling from 80ish to 2 ppm!
Then if i test the second one by itself it also reads 2 ppm 
Th back one used to get up to about 40ppm before i needed to change the front one . Im confused any help , ideas 
Have given them a good shake , only making about 1200 litres a month , Surley it should last longer than this ! Only about 2 months since i changed the back one .

[The Jester of Wibbly]

Sounds like it's a tds calibration issue.  Try another reader and it my be 000 anyway.

[george renwick]

Have two tds meters they are both reading the same 2

[֍Winp®oClean֍]

Start with the obvious... is the flow direction of the newest vessel correct?

Is the riser tube inserted and sealed correctly inside the head?

Are all/any internal strainers clear and not blocked?