Rechecking Conductivity probe in 5300 not same why

[Jyetman]

When I calibrated my new apex probe now nearly a week old I get 34.6 in 5300 solution. When I put in tank I get a reading of 33.8 for last couple days it goes between 33.6 and 33.8 stable I guess. Today I put the probe back in the original saved 5300 solution it reads 40.4 instead of 34.6 why??? I made sure probe was dry, floated the test bag in tank water with temp probe but getting a different reading? If I put the probe back in tank it reads 34.1 what is going on here?

Edit: after 10 minutes its down to 33.9 - 34.0 so its slowly returning to 33.8 but why isn't the test solution the same?

 

[slief]

When I calibrated my new probe now nearly a week old I get 34.6 in 5300 solution. When I put in tank I get a reading of 33.8 for last couple days it goes between 33.6 and 33.8 stable I guess. Today I put the probe back in the 5300 solution it reads 40.4 instead of 34.6 why??? I floated the test bag in tank water with temp probe but am I getting a different reading? If I put the probe back in tank it reads 44.1 what is going on here?

Where was the temp probe for the PM2 when you put the CondX probe in the 53000 solution? Did you rinse the probe and let it dry? Did you let it settle out in the solution? It can take several minutes to settle. Allowing it to fully settle before confirming the calibration is important for this reason.

 

[Jyetman]

Where was the temp probe for the PM2 when you put the CondX probe in the 53000 solution? Did you rinse the probe and let it dry? Did you let it settle out in the solution? It can take several minutes to settle. Allowing it to fully settle before confirming the calibration is important for this reason.

The temp probe is connected to the PM2 and is in tank so is the 5300 test bag. I didn't rinse the probe in RO or dry it completely maybe that is the reason. Possible the used 5300 test solution is contaminated?

 

[oseymour]

This probe is very susceptible to interference. Make sure the cable for the probe is not close to any other cable, especially power cables.

 

[Jyetman]

This probe is very susceptible to interference. Make sure the cable for the probe is not close to any other cable, especially power cables.

Can the cable be wrapped in aluminum foil to help shield any interference?

 

[oseymour]

Can the cable be wrapped in aluminum foil to help shield any interference?

I'm not sure, I ended up having to re-route my entire Apex cable setup to get it to work.

 

[Jyetman]

I'm not sure, I ended up having to re-route my entire Apex cable setup to get it to work.

Currently my tank readings properly compare its just rechecking the calibration fluid that is way off. I think the saved fluid is contaminated. I'll just stick with the current calibration since 34 is spot on.