Help! pH probe and Salinity probe not accurate.

reefandreptileautomation · Apr 26, 2019

Hello, I just purchased 2 brand new probes. Conductivity and double jointed pH probe. They both are plugged directly into my Apex 2016 unit. They are off by about .1 pH and 1 ppt respectively. I have a portable pH tester and it reads .1 higher every time. I have a PM1 on another tank hooked up to the same Apex unit and it reads exactly the same as the pH tester. I have a PM2 on the other tank as well and same, the salinity is spot on with my refractometer and my Hanna portable salinity tester. I have no idea why one tank (where the probes are directly to the base unit) are off but the ones on the PM1 and PM2 are spot on.

I've done the following:
- tried reading a cup of water outside the tank, same results.
- turned off all items in the tank
- tried reading the calibration fluid again (brand new fluid), also placed it into the sump for about 15 min to temperature compensate.
- move the probe away from any possible electrical cords
- calibrated multiple times

I give up with this but it is clearly not accurate. I notice throughout the day the pH probe will sometimes drift down and the salinity has also drifted over the past few days. Ph from 8.0 to now 7.78. The pH probe does fluctuate throughout the day but the average is a drop. The salinity has gone from 34-31 in a matter of 3-4 days and nothing has changed. The salinity is about 33 right now from other sources including my ICP test. The probe shows current 31.2.

Any assistance would be greatly appreciated.

Waters · Apr 26, 2019

If it is only off .1 and 1ppt then you are ahead of the game lol. Most of the Apex probes are not accurate......I just use them just to watch for swings rather than actual numbers. The salinity probe drifts more than others due to micro bubbles or buildup on the probe tip. As long as the readings stay somewhat consistent, I would just use them to watch for changes and double check parameters with other methods. If I remember correctly, the salinity probe has a compensation setting that allows you to slightly calibrate them as long as you know the actual reading (I could be wrong though).

reefandreptileautomation · Apr 26, 2019

The salinity probe has a TC but that doesn't seem to effect the output reading. The pH probes being off by .1 is worrisome.

rkpetersen · Apr 26, 2019

You're doing all the right things but there's one other thing you can try with the salinity probe.

Disconnect the probe. Do a manual calibration. Just go through all the steps quickly. Reboot the Apex. Plug the probe back in.
Now try a manual (not automatic) calibration again, but do it in Apex Local, not Apex Fusion.
Use a new calibration packet and have it at tank temperature, and make sure temperature compensation is turned on.

pH is normally cyclic, it should rise during the day and fall at night.
You can attempt resetting and recalibrating the pH probe as outlined above for the salinity probe.

reefandreptileautomation · Apr 26, 2019

Ok, I will give that a try. I upgraded from my Apex Classic to the Apex 2016 and did adopt data. When I did that it took the calibration data also. Which I had to recalibrate of course. I wonder if that is the whole issue.

n2585722 · Apr 27, 2019

How long have you had your new probe in the tank water? If they are new give them a week and then calibrate again.

reefandreptileautomation · Apr 27, 2019

Many weeks now. I have calibrated it a few times. I purchased a new probe so going to give that a go.

sergebmw2 · Apr 28, 2019

I just got my new apex along with the new probes calibrated them all and I still have a way off reading on orp and salinity. Will wait 1-2 weeks to calibrate again.

sergebmw2 · Apr 28, 2019

Here are the readings

Screenshot_20190427-152442_Apex%20Fusion.jpeg

n2585722 · Apr 28, 2019

Give the ORP a couple of days after having it in the calibration fluid. Mine always drops after it is in the cal fluid for awhile. Also on the ORP once it has settled you are more interested in a change from the normal readings for your tank than a specific reading. So you will have to have it running for several weeks to get a normal pattern. The readings will naturally vary during the 24 hour period.

On the salinity probe when you calibrate make sure all the air bubbles are out of the probe. Since you have a low reading after cal you may have an air bubble in the probe causing a lower reading.

sergebmw2 · Apr 28, 2019

n2585722 said:
Give the ORP a couple of days after having it in the calibration fluid. Mine always drops after it is in the cal fluid for awhile. Also on the ORP once it has settled you are more interested in a change from the normal readings for your tank than a specific reading. So you will have to have it running for several weeks to get a normal pattern. The readings will naturally vary during the 24 hour period.

On the salinity probe when you calibrate make sure all the air bubbles are out of the probe. Since you have a low reading after cal you may have an air bubble in the probe causing a lower reading.

Thanks for the info. I will give it a week and recalibrate. Only reason I ask about the ORP is because most people seem to be reading in the hundreds range and mine is just under a hundred. Thanks for the advice.

reefandreptileautomation · Apr 28, 2019

Replaced both probes and that did the trick. For anyone else experiencing these issues it is worthless to contact Neptune as they believe their product doesn't break or has any issues. After hours of calibrating and trying multiple fluids it ended up being 2 bad proves which I thought they were.

n2585722 · Apr 29, 2019

Derrick Picker said:
Replaced both probes and that did the trick. For anyone else experiencing these issues it is worthless to contact Neptune as they believe their product doesn't break or has any issues. After hours of calibrating and trying multiple fluids it ended up being 2 bad proves which I thought they were.

Glad to here.

sergebmw2 · May 1, 2019

After 5 days these are the results for orp I just left it be no calibration is needed per BRS instructions.

Screenshot_20190429-014431_Apex%20Fusion.jpeg

Screenshot_20190501-135853_Apex%20Fusion.jpeg

smartwater101 · May 1, 2019

Derrick Picker said:
Replaced both probes and that did the trick. For anyone else experiencing these issues it is worthless to contact Neptune as they believe their product doesn't break or has any issues.

It took awhile but they finally replaced my pH probe that wasn't accurate on DAY ONE. And I'm not sure they actually replaced it as the email said they "diagnosed and repaired" it. I'm sticking with Pinpont and Milwaukee from now on.

n2585722 · May 1, 2019

sergebmw2 said:
After 5 days these are the results for orp I just left it be no calibration is needed per BRS instructions.

It looks like the ORP is starting to rise. You may want to calibrate the salinity again. Make sure there are no air bubbles trapped in the probe when calibrating. I think Neptune has a how to somewhere for this.

sergebmw2 · May 1, 2019

n2585722 said:
It looks like the ORP is starting to rise. You may want to calibrate the salinity again. Make sure there are no air bubbles trapped in the probe when calibrating. I think Neptune has a how to somewhere for this.

Yeh iam waiting 2 more days and I got all the air bubbles out of it. I watched that video like 3 times to make sure.. hansk for the suggestion [emoji106] guess most people recomend just waiting at least a week to recalibrate..