PH probe/module Issue

rob safron · May 2, 2019

So I have 3 pH probes, one in the calcium reactor, one in the sump and the third is the display tank. As the pic shows, the sump and display values became about .15 off each other after the last routine calibration. Since that happened, I have calibrated multiple times and purchased a new probe thinking the DT probe that went way down after the first cal was broke. I have also put the DT probe on the sump module and sump probe to the DT module and values just flip flopped. So I assume the probes are not the issue. Both also read accurately when placed in cal solution. Could it be a bad module? How do I know which is correct reading or which module is bad??

ReefAddiction34 · May 2, 2019

First of all.. why the hell do you have three pH probes in one tank lol. Personally I’d just stick with one (unless the calcium reactor one is needed), and I wouldnt go chasing numbers especially if your system in doing great and your livestock is healthy.
That being said, I had a similar issue with my pH probe after calibrating. It was running well, my pH was accurate and seemed reasonable. I then made the mistake of calibrating it and the stuff hit the fan... the pH was reading High 6 to low 7’s. The tank was doing fine. All corals and fish were healthy... it was just inaccurate. Called Neptune and they gave me the run around having me do a lot of things to look for stray voltage, EMI (electromagnetic interference), buying a new pH probe, sending in my PM1 module etc... it was a pain. After all was said and done, the dang thing never corrected. That is until I recently moved. I hooked the apex back up to give it a try and boom the numbers were perfect 8.1-8.3 ish.
So maybe there is something to EMI and what things you have on near the tank, I’m not sure.
I think my bigger point here is that I would t chase the number of things are going well. It sucks, but you might have to wait it out and see if it corrects, or just mentally make corrections based on what you think the tank is most likely at and what the controller/fusion tells you.

rob safron · May 2, 2019

Ha. I like data. I like the calcium reactor one in case the co2 tank or pump fails. I will get a ph alert. I travel a lot for work. No real reason for having 2 for tank and sump, just ended up with them. Seems if it were electrical interference they would have been off all along. They only went out of range after a stupid cal. I don’t chase pH, never add anything as everything is growing fine and I will just always have a lower and wide fluctuation. Again, I just like data and trends since I’m gone a lot and don’t really have a tank sitter. Family has noooooooo interests at all.

ReefAddiction34 · May 2, 2019

Lol story of my life.. wife really has no interest in it. She caught me staring at my protein skimmer and basically laughed at me.
I wish I had a better explanation honestly. I did the same thing, just cleaned and calibrated my pH probe trying to be a good reef keeper lol and the darn thing is off by a point almost crazy. But after moving and setting it back up, it’s working perfect. I’m not touching it or attempting to recalibrate it unless it’s wayyyy off and just useless anyways. Neptune had no explanation for me. Not bashing them, but just not helpful honesty in resolving the matter.

smartwater101 · Jul 12, 2019

rob safron said:
So I have 3 pH probes, one in the calcium reactor, one in the sump and the third is the display tank. As the pic shows, the sump and display values became about .15 off each other after the last routine calibration. Since that happened, I have calibrated multiple times and purchased a new probe thinking the DT probe that went way down after the first cal was broke. I have also put the DT probe on the sump module and sump probe to the DT module and values just flip flopped. So I assume the probes are not the issue. Both also read accurately when placed in cal solution. Could it be a bad module? How do I know which is correct reading or which module is bad??

I had the same issue. I have 2 Pm1 and the base unit. So thats 3 connections I was using, and I cycled through FOUR different brands of probes. (Trying to figure out if a certain module/probe combo might be problematic.) ALL readings are fine for about a day and all will drift afterwards. One of the modules is now linked to the Alkatronic, which sends a consistent digital signal... and the Apex can't even stay on point.

Neptune Support tells me its within a reasonable margin. Which is nonsense. :/ Most people accept it because "don't chase pH" has been such a common saying for so long, so I doubt there is really any incentive for Neptune to improve. While pH may not be the most important part of the system, I expect better accuracy than 1.5 deviation. I'd imagine it's even more important for your calcium reactor. Perhaps there just isn't a brand out there that is actually consistent/accurate? Idk... maybe my expectations are too high...

BonelessEvil · Jul 28, 2019

smartwater101 said:
I had the same issue. I have 2 Pm1 and the base unit. So thats 3 connections I was using, and I cycled through FOUR different brands of probes. (Trying to figure out if a certain module/probe combo might be problematic.) ALL readings are fine for about a day and all will drift afterwards. One of the modules is now linked to the Alkatronic, which sends a consistent digital signal... and the Apex can't even stay on point.

Neptune Support tells me its within a reasonable margin. Which is nonsense. :/ Most people accept it because "don't chase pH" has been such a common saying for so long, so I doubt there is really any incentive for Neptune to improve. While pH may not be the most important part of the system, I expect better accuracy than 1.5 deviation. I'd imagine it's even more important for your calcium reactor. Perhaps there just isn't a brand out there that is actually consistent/accurate? Idk... maybe my expectations are too high...

both my Neptune systems probe and the new BRS probe I purchased are off by about 0.3 (from Red Sea test kit). Is this a problem? Should I also be concerned this is NOT within a reasonable margin? Or is this okay? By the way, it passed the automatic calibration within the apex. Should I use manual for better results?