Apex probe reading issues

dakoop · Apr 28, 2022

My ph and salinity were reading low on my apex. I tested salinity with my calibrated refractometer and it measured correctly @ 35, apex showed 31. Ph was reading 7. I ordered calibration packets thinking that was the issue. Calibrated salinity without issue. The ph read way off. It settled on 300 for the 7.0 solution and q250 for the 10.0
Now the salinity in the tank reads 19, shook out the bubbles
The ph reads 6.8 but isn't accurate when reading the calibration solutions.

Do I have a couple of bad probes?

((FORDTECH)) · Apr 28, 2022

dakoop said:
My ph and salinity were reading low on my apex. I tested salinity with my calibrated refractometer and it measured correctly @ 35, apex showed 31. Ph was reading 7. I ordered calibration packets thinking that was the issue. Calibrated salinity without issue. The ph read way off. It settled on 300 for the 7.0 solution and q250 for the 10.0
Now the salinity in the tank reads 19, shook out the bubbles
The ph reads 6.8 but isn't accurate when reading the calibration solutions.

Do I have a couple of bad probes?

For what it’s worth the salinity probe is junk very hard to get accurate consistant readings. As far as calibration being off on any probe from my experience I e had issues doing this from iPhone but when I use pc the calibrations worked and saved to the apex

Jon's Reef · Apr 28, 2022

I have had a lot of success with adding flow to the salinity probe. I was inspired by the VCA SPS kit. In my old system I set a small pump to gently blow over the tip, in my new setup the flow of the sump goes right up into the probes. It will require calibration in the flow, so I ensure the system is dead on 35 ppt via an alternate test and use the actual probe placement in the sump for the 53k part of the calibration. If any of the probes start to get flaky, soak them in citric acid for 15-20 min.

35.4 is my target value (35.4 = 35)

dakoop · Apr 28, 2022

I did try the calibration on my android. Guess I can try computer

Yevoc · Apr 28, 2022

I had a head unit fail that was warrantied by Neptune.

I got the new unit and installed the old pH and Salinity probes and they would not calibrate to the new for anything.

These worked just fine on the prior head unit.

I was pulling my hair out. So I ended up opening a ticket with Neptune.

The 2 tips they gave me.

1) Use the manual calibration so you can watch the numbers settle yourself.

2) Use the Neptune local connection instead of the cloud. They said the cloud sometimes introduces lag.

I had to do both of those once. Back to perfect.

((FORDTECH)) · Apr 28, 2022

Jon's Reef said:
I have had a lot of success with adding flow to the salinity probe. I was inspired by the VCA SPS kit. In my old system I set a small pump to gently blow over the tip, in my new setup the flow of the sump goes right up into the probes. It will require calibration in the flow, so I ensure the system is dead on 35 ppt via an alternate test and use the actual probe placement in the sump for the 53k part of the calibration. If any of the probes start to get flaky, soak them in citric acid for 15-20 min.

35.4 is my target value (35.4 = 35)

Citric acid does not damaged probe? At what ratio do you use ?