Conductivity probe not calibrating

[Miami Reef]

I made a 53mS/cm conductivity standard using 0ppm TDS RO/DI water (182g) with Morton iodized sea salt (6.2g)

I used a scale with an accuracy of 0.1g to weigh the water and the salt. I calibrated the scale prior with a 500g weight standard.

I followed the Neptune Apex instructs. I dried out the probe until the reading with acceptable and stable, then I dipped the probe into the solution and gently stirred any air bubbles out from the probe. I allowed the reading to become adequate and stable before I hit “complete.

However, the APEX is still reading the standard as 38ppt. I know I did everything correctly, and I have successfully calibrated my conductivity probe in the past. I’m not sure why it’s not reading the calibrated solution correctly.

I will try unplugging the conductivity probe and possibly even resetting the apex.

 

[Miami Reef]

The title should say probe. My phone autocorrects my words and I should have double checked the title.

 

[I never finish anythi]

The title should say probe. My phone autocorrects my words and I should have double checked the title.

Nice spot

 

[Peace River]

The title should say probe. My phone autocorrects my words and I should have double checked the title.

Fixed!

 

[SteveMM62Reef]

I have a conductivity probe too, but you can’t calibrate the reading. As I understand, the Probe is Titanium. I brushed a strong solution of Citric Acid on the Probe, with an artist brush. It is closer to the correct reading. Next time I do a complete tear down of my Fluval G3, I will try for a longer Citric Acid contact time. Hope this helps.

 

[Rmckoy]

Is this standard for conductivity or specific gravity ?

I know you can’t use conductivity solution to calibrate a refractometer and you can’t use refractometer solution to calibrate Hanna salinity instrument

 

[Miami Reef]

I think I got it fixed! Give me a second. Let me make sure before I state how I did it.

 

[Miami Reef]

Is this standard for conductivity or specific gravity ?

I know you can’t use conductivity solution to calibrate a refractometer and you can’t use refractometer solution to calibrate Hanna salinity instrument

It’s a standard for conductivity. Yes, you are correct that refractometers and conductivity meters use different solutions. :)

 

[Miami Reef]

This is what it’s saying. I tried rebooting and disconnecting everything and then plugging in. Not sure what to do next.

I am all up to date. Maybe I should reset my Wi-Fi. I’m not sure. Sometimes leaving things alone and then coming back to them works.

 

[Garf]

This is what it’s saying. I tried rebooting and disconnecting everything and then plugging in. Not sure what to do next.

I am all up to date. Maybe I should reset my Wi-Fi. I’m not sure. Sometimes leaving things alone and then coming back to them works.

Not got an Apex but I wonder if it’s one of those systems that will not accept the calibration solution if it out of the expected range. Personally I would try making up more of the calibration solution to say 500grammes, which is where your scales are calibrated at. I have not checked your recipe for making the DIY solution however. You sure your using the conductivity probe one?

 

[Miami Reef]

This is the exact issue I’m facing: https://forum.neptunesystems.com/showthread.php?21085-Apex-2016-Conductivity-Probe-not-calibrating

 

[Randy Holmes-Farley Verified Community Expert]

Was the temp an issue? The device needs to know the temp of the standard.

 

[Miami Reef]

Was the temp an issue? The device needs to know the temp of the standard.

Nope. Impossible. I ensured that the standard was sitting in a plastic water bottle (rinsed 3 times with the standard) in my sump, which was right next to the temp probe, and then I allowed it to equilibrate with the same temperature as the probe. The tank was around 25C. I even used a thermometer.

I am pretty confident it’s something wrong with the apex. I tried calling them, It‘s holiday season and they seem to be closed, but I will make sure I get customer support.

I will keep this updated.

 

[Lbrdsoxfan]

I upgraded to a A2 a few weeks ago and have the same issue. My probe reads 3 ppt higher. It did okish with a PM2 on a classic apex. Hope you have a solution, I'm at my wits end with it.

 

[Randy Holmes-Farley Verified Community Expert]

Nope. Impossible. I ensured that the standard was sitting in a plastic water bottle (rinsed 3 times with the standard) in my sump, which was right next to the temp probe, and then I allowed it to equilibrate with the same temperature as the probe. The tank was around 25C. I even used a thermometer.

I am pretty confident it’s something wrong with the apex. I tried calling them, It‘s holiday season and they seem to be closed, but I will make sure I get customer support.

I will keep this updated.

Ok, that sounds appropriate. :)

 

[killer2001]

Do you have the TC factor enabled on the salinity probe in Apex? I think the general value is 2.1 to 2.3.

 

[Miami Reef]

Do you have the TC factor enabled on the salinity probe in Apex? I think the general value is 2.1 to 2.3.

Yep. It’s 2.2.

 

[killer2001]

When I was calibrating mine, I let it soak in RODI for about 15 minutes before beginning the Apex process for calibration. And even after all these steps, if the probe is not displaying what I wanted, I further adjusted my TC factor until I got the appropriate 35ppt. Not sure if thats the best method, but so far my Apex probe matches my Milwaukee refractometer close enough so I am content (for now).

 

[Miami Reef]

When I was calibrating mine, I let it soak in RODI for about 15 minutes before beginning the Apex process for calibration. And even after all these steps, if the probe is not displaying what I wanted, I further adjusted my TC factor until I got the appropriate 35ppt. Not sure if thats the best method, but so far my Apex probe matches my Milwaukee refractometer close enough so I am content (for now).

Thanks Killer,

My issue is that the probe doesn’t let me calibrate it anymore.


I just googled and I read 2 separate posts that said they were successful when they used a computer to calibrate the probe.

It can’t hurt to try. :)

I’ll get back to you guys. :)

 

[Miami Reef]

Update. Didn’t work.

This seems like a job for customer service.