Inline TDS meter

[Daftoldgit]

Ok so my meter has 2 probes one for RO and one for DI

The DI one matches the handheld meter reading, but I tried comparing the water from the RO one with the handheld the other day,  and it was wildly different to what the inline one is saying. (double the TDS) I never thought to check it before as its accurate on the DI reading, so all these years I've been getting a false RO reading without knowing!

 

[Deleted member 7446]

Ok so my meter has 2 probes one for RO and one for DI

The DI one matches the handheld meter reading, but I tried comparing the water from the RO one with the handheld the other day,  and it was wildly different to what the inline one is saying. (double the TDS) I never thought to check it before as its accurate on the DI reading, so all these years I've been getting a false RO reading without knowing!

If your inline is an HM digital then it won't lie. You have to ensure that the two prongs on the probes are horizontal to the water flow to ensure a correct reading. 

The RO reading will be higher than the DI out. 

 

[Daftoldgit]

Yeah it's an HM one, they both are. just checked and the probe's pretty much horizontal

the RO reading on the inline one says one thing, but if I  fill a cup direct from the RO it reads twice as much as what the inline one says, I'm wondering if there's a bad connection in the wiring or something.

So if the hand held one is correct it's new membrane time, if the hand held one is right I save a few quid!

 

[ched999uk]

Have you tried swapping the 2 probes around? See if 1 agrees with the other probe or the handheld. Double check any joints as any excess resistance (poor connection) will give false readings.

Let us know how you get on.

 

[Daftoldgit]

Have you tried swapping the 2 probes around? See if 1 agrees with the other probe or the handheld. Double check any joints as any excess resistance (poor connection) will give false readings.

Let us know how you get on.

Good thinking!  I'll try that at the weekend, thanks

 

[Master Jedi Alejandro]

@doug atkinson should be able to help with this

 

[spruce]

Get some TDS testing/calibration fluid.

 

[doug atkinson]

Is the probe linear with the water flow. Also good to give them a wipe with alcohol as they can start give false reading with being sat in hard water.

 

[Jango]

Just one thing to check, I had a similar thing. When I took the back off the in-line meter the tiny white clip  that holds the wires had slightly dropped. Once I pushed that back in securely everything worked as it should. Just worth checking. 

 

[Daftoldgit]

Ok so when I tried to get the probe out the john guest fitting is jammed solid, I'm kinda loathe to force it incase it breaks and leaks water.. so Im just going to live with it for the moment, thanks for all the suggestions

 

[Jango]

Ok so when I tried to get the probe out the john guest fitting is jammed solid, I'm kinda loathe to force it incase it breaks and leaks water.. so Im just going to live with it for the moment, thanks for all the suggestions

Mine are fitted into John Guest  fittings. If yours are like mine, right in the centre of where the probe goes you will see a circle that slightly protrudes. Push that in and it will release the probe. I’ll take a photo of mine and post. 

 

[Deleted member 7446]

Where the probe stem enters the John Guest fittings you simply hold the probe and press in the retaining collar In while giving the probe a little push then pull it out 

Ensure your water flow is isolated first or you'll get an unexpected drink