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Thread: pH Over 12

  1. #1
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    pH Over 12

    Just set up new tank. calibrated the pH probe and all seems to be fine. Yet in salt water in tank its reading over 12! Checked against another test kit and ph is about 8-ish... but as soon as probe goes in either the sump or display it is reading 12. I've not got it crossing any wires as tested that.

    It is mounted in holder and salinity and temp are ok. ORP is creeping up (as expected to stabilise), just the pH is way out... I would have expected the salinity to be showing weird if anything...

    is the probe damaged? How can i check.

    Any ideas? ;-/

  2. #2
    Master Control Freak aquamanic's Avatar
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    A pH reading of 2 or 12 is indicative of a failed probe or port.

    Is this a new probe? Make sure the BNC connector is not shorting against the ORP connector next to it.
    Al

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    thanks - what i feared - but how come i can calibrate it then? the whole system is less than 2 months old so not sure what is going on? [resume i can take back to my lfs? The probe is direct into the apex. unsure what you mean about the ORP shorting? how? they aren't crossing any wires...

  4. #4
    Frequent Contributor zombie's Avatar
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    Another possibility is that you calibrated it incorrectly. If you calibrated it using 7.01 solution, but selected the option for 4.01 for low and then used 10.01 and checked the option for 7.01 for high, a reading of 12 would not be out of the question. Recalibrate it using the display, making sure to select the correct calibration solutions and see if the reading changes.

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

  5. #5
    Master Control Freak aquamanic's Avatar
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    I doubt you can calibrate it. If you can and it reads 7.0 or 10.0 in calibration solution but then jumps to 12 in the tank, then that's something I've not seen. Are you certain you have it connected to the pH jack and not the ORP jack?

    By shorting, I mean there are two BNC connectors on the controller and they're right next to each other. It's a tight fit between the ORP and pH probes. If those touch, then you're shorting one against the other.
    Al

    I do not work for Neptune. Please do not send me PMs with technical questions or requesting assistance - use the forums!
    For Neptune support send an email (don't call) to: [email protected] .
    Manuals for all products including the
    Comprehensive Reference Manual can be found here.

  6. #6
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    definitely was 7 - zombie. last night the ph in tank was 7.97. Woke up this morning and is 12.2. naturally i panicked... but at 2am it spiked from 8 to 12 and back again several times... now permanently on 12.

    i switched everything off on tank and waited 20 mins... see if electrical spike - but still the same.

    just can't figure how in the solutions it is reading 7 and 10... in tank its 12?

  7. #7
    Master Control Freak RussM's Avatar
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    Shut off ALL electrical devices associated with the tank except the Apex.... Pumps, heaters, etc. See if it reads normally in the tank
    Please do not send me PMs with technical questions or requesting assistance - use the forums for Apex help. PM me ONLY if the matter is of a private or personal nature. Thanks.

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    i did that earlier Russ... nothing changed. How long would you leave everything off for to notice a difference?

  9. #9
    Frequent Contributor zombie's Avatar
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    Quote Originally Posted by Dean Donaldson View Post
    i did that earlier Russ... nothing changed. How long would you leave everything off for to notice a difference?
    It would be almost instantaneous

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

  10. #10
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    everything is shut down right now. nothing running. even rebooted apex. same thing. 12.2....

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    Screen Shot 2015-01-07 at 23.00.20.png

    this is screen shot of controller for last 24 hours. Initially was ok. Sometime in early hours went haywire... and only when i have had it offline today to recalibrate are the lower spikes.

  12. #12
    Frequent Contributor zombie's Avatar
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    That is most definately a faulty probe or port. Contact support. If you have a friend that has a working pH probe, you could narrow it down to the probe or the port to speed up the process, but either way it lokks like something is gonna need repair/replacement.

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

  13. #13
    Frequent Visitor 2mk's Avatar
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    This question may sound dumb. I have calibrated my ph probe and assume it is correct. It's been running some days now. What can I use to check the PH in a reliable way other than the probe to determine if the probe is calibrated accurately?

    panel.jpgph.jpg

  14. #14
    Frequent Contributor zombie's Avatar
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    You check it with calibration solution.

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

  15. #15
    Frequent Visitor 2mk's Avatar
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    I don't mean the probe itself. I mean checking the water ph itself and match it to the probe readings. Other then dip sticks and test kits, is there any other way to test it? I don't have anything to test it with.

    or you meant to stick the probe back in the calibration fluid to see if it reads what the fluid is at?
    When You're a NOOB, You need lots of help all the time

  16. #16
    Frequent Visitor rkpetersen's Avatar
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    Yup, you can check whether your calibration is correct or whether the probe has drifted by using the same calibration standard solutions.

    As far as other means to check your water's pH, beyond the normal pH test kits, you can always get another digital pH meter; several companies make hand-held ones. But then you wind up wanting to calibrate those too, which again takes you back to the calibration buffer solutions.

  17. #17
    Frequent Visitor 2mk's Avatar
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    Thanks
    When You're a NOOB, You need lots of help all the time

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