New Apex - pH and conductivity probes

[Tomoko Schum]

Hi y'all,

I am new to Apex. I got a brand new Apex 2016 and started setting it up last night. I am having an issue with the pH and conductivity probes.

When I tried to calibrate the pH probe, the iPhone app hung up and I could not complete the calibration with the first reference solution (pH7.) After waiting several minutes, I cancelled the calibration. When I tried to calibrate with the same solution again, the same thing happened. I checked the connection on the base unit and found that the probe was securely connected to the correct location. Do you think that the pH probe is defective?

As for the conductivity probe, I see the reading is way too low. The graph on apex.local started at 32.6 last night and it is trending downward (31.9 currently.) I checked the salinity with Milwaukee digital refractometer and another hand held refractometer and confirmed that both readings were 1.026. I did not float the packet of the reference solution in my tank before the calibration to equalize the temperature of the solution to the temp of the tank water. Do you think this might be the issue?

[zombie]

On brand new probes I always let them soak in my tank for at least 24 hours cause they are usually too dry to take calibration well (water needs to build up in the pores of the glass and get a coating film on the outside of the glass). Storage solution is supposed to prevent this issue but there are usually some dry spots after shipping.

For the pH, try manual calibration instead of auto calibration. Auto is very finicky. I let my probe sit in each solution for 5 minutes then move to the next.

For the conductivity, not matching tank temp can cause major errors, and not getting the probe slightly wet during the dry stage also causes problems (it's best to have it soak overnight, lightly rinse off in RO, and lightly pad with a paper towel. You want a light film of RO, but no big droplets).

You might be an engineer if...You have no life and can prove it mathematically.

[Tomoko Schum]

On brand new probes I always let them soak in my tank for at least 24 hours cause they are usually too dry to take calibration well (water needs to build up in the pores of the glass and get a coating film on the outside of the glass). Storage solution is supposed to prevent this issue but there are usually some dry spots after shipping.

For the pH, try manual calibration instead of auto calibration. Auto is very finicky. I let my probe sit in each solution for 5 minutes then move to the next.

For the conductivity, not matching tank temp can cause major errors, and not getting the probe slightly wet during the dry stage also causes problems (it's best to have it soak overnight, lightly rinse off in RO, and lightly pad with a paper towel. You want a light film of RO, but no big droplets).

You might be an engineer if...You have no life and can prove it mathematically.

Thank you very much for the tips! I have to wait till I get hold of more reference solutions, but I will try them for sure

Tomoko

[rkpetersen]

It took me a few tries to get everything properly calibrated as well, but since then it's all been surprisingly accurate and stable. I'm coming up on a 'scheduled' cleaning and re-calibration of all my probes, but I'm loathe to do it as they are all currently working so well. (Also, with 6 probes, a fair amount of work.)

[Tomoko Schum]

Thank you for the comment, rkpetersen.

What is the recommended frequency for the re-calibration?

Tomoko

[zombie]

Thank you for the comment, rkpetersen.

What is the recommended frequency for the re-calibration?

Tomoko

pH once every month or 2. Conductivity 3 or 4 times a year. ORP doesn't need calibration unless being used to control a sulfur denitrator or ozone generator.

You might be an engineer if...You have no life and can prove it mathematically.

[Tomoko Schum]

pH once every month or 2. Conductivity 3 or 4 times a year. ORP doesn't need calibration unless being used to control a sulfur denitrator or ozone generator.

Thank you for the recommendation

[Todd]

You can periodically check them with calibration fluid and actually only re-calibrate if needed.

[Tomoko Schum]

You can periodically check them with calibration fluid and actually only re-calibrate if needed.

Great!

[Tomoko Schum]

So, I soaked the probes for more than 24 hours and recalibrated pH probe and salinity/conductivity probe. This time pH probe calibrated with auto calibration without failing. However, it reads very low. It reads 0.5 too low. The reading of my reef tank water was 7.6 and the reading on my freshwater planted tank was 6.2. It read the 7.01 calibration solution as 6.51. Should I recalibrate the pH probe by manual calibration?
As for the conductivity probe, it failed every time I tried it this time.

After the last post I made here, my tank started leaking and I ended up replacing my tank. I took everything off line and kept all the probe in a jar of tank water to keep them from drying out. It was like soaking them for awhile after all. When I reconnected my Apex, it failed to connect to wifi. Since the reset button did not work, I connected the Apex via an ethernet cable as Neptune instructed and got my Apex on wifi. Then, I started calibrating the probes. The temp probe works fine, but as I reported above, I am having issues calibrating the conductivity and pH probes.

So, where do I go from here? Should I go through calibration manually? I saw some parameters that I need to set if I were to do so. What should I plug in there? Can I get some recommendations on how to proceed?

[zombie]

So, I soaked the probes for more than 24 hours and recalibrated pH probe and salinity/conductivity probe. This time pH probe calibrated with auto calibration without failing. However, it reads very low. It reads 0.5 too low. The reading of my reef tank water was 7.6 and the reading on my freshwater planted tank was 6.2. It read the 7.01 calibration solution as 6.51. Should I recalibrate the pH probe by manual calibration?
As for the conductivity probe, it failed every time I tried it this time.

After the last post I made here, my tank started leaking and I ended up replacing my tank. I took everything off line and kept all the probe in a jar of tank water to keep them from drying out. It was like soaking them for awhile after all. When I reconnected my Apex, it failed to connect to wifi. Since the reset button did not work, I connected the Apex via an ethernet cable as Neptune instructed and got my Apex on wifi. Then, I started calibrating the probes. The temp probe works fine, but as I reported above, I am having issues calibrating the conductivity and pH probes.

So, where do I go from here? Should I go through calibration manually? I saw some parameters that I need to set if I were to do so. What should I plug in there? Can I get some recommendations on how to proceed?

You need to do manual calibration (auto sucks don't even bother with it). Also make sure when you do the conductivity probe that for the dry step you lightly rinse in RO and pad dry with a paper towel (dont let it dry for a day like the BRS video suggests it doesn't help). For the wet step float the calibration packet in your tank for 30 minutes and when you place the probe in solution make sure all bubbles are dislodged and the packet is touching tank water to keep it from cooling down (I use two magnets so I don't have to hold it).

You might be an engineer if...You have no life and can prove it mathematically.

[Tomoko Schum]

i started calibrating my ph probe manually, but it is taking a long time for it to settle. it's been sitting foe 7 or so minutes in ph 7.01 calibration solution (step 2), but the number is at 705. how long does it suppose to take?

[Tomoko Schum]

Since manual calibration just won't settle for me, after trying it twice, I ended up calibrating the probe again in auto. This time the probe shows 8.17 value, which is closer to the actual value. I need to verify it with an accurate pH meter tomorrow. My lab grade hand held pH meter is out of calibration, but I can take my water into the wet lab at work.

[zombie]

i started calibrating my ph probe manually, but it is taking a long time for it to settle. it's been sitting foe 7 or so minutes in ph 7.01 calibration solution (step 2), but the number is at 705. how long does it suppose to take?

About 5 minutes is usually safe. The actual value on screen isn't the part that matters. The part that actually matters is that the number on the screen hasn't changes for at least the last 30 seconds to a minute (think of it like old school microwaving of popcorn where the number changing is a pop).

You might be an engineer if...You have no life and can prove it mathematically.

[idpitt]

The background:

New Apex 2016 ( replaced a fubar Classic). New probes. Probes have sat in the tank for a week. I bought two 7/10 sets of calibration fluid since I didn't have any luck the first time around. I've:

- Floated the pair of fluids in the tank for 30 minutes to acclimatize.
- Placed some tank water in mug and placed the fluid pouches in that for the actual testing.
- Used manual calibration
- Left the probe ( having swished it around to remove any bubbles ) for 5 minutes plus in each of the fluids during the manual calibration.
- In the 7.0 fluid, the probe read 8.45.
- In the 10.0 fluid, the probe read 10.1.


After calibration, I'm reading a 9.03 pH in the tank ( a color based chemical test indicates more of an 8.5). The old probe and Apex measured about this (maybe a bit higher) so I tend to believe the color result.


I did the calibration again today. Same result. in RODI water, the probe reads in the middle 8s. If I switch on PH2 on the base unit and plug in the same probe, I get 8.36 in the tank and around 6.8 in RODI water.


What am I doing wrong?

[idpitt]

Neptune support helped me fix this. Disconnect the probes, run a calibration then reboot the Apex. Reconnect the probes and do another real calibration. All good now.