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Thread: erratic temp and ph readings

  1. #1
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    erratic temp and ph readings

    Several months ago 1 of 2 of my ph probes has been giving erratic readings at all times of the day. One minute it may read a normal 8.2 and the next it will jump to 18.5 and stay there for several hours or days. Sometimes it will read 3.5 and again stay there for several hours or days. The other probe works just fine.

    I've switched the probes in their ports to make sure it wasn't a bad probe. Probes were only a couple months old when this first started happening.

    Just recently the other probe started doing the same but not as frequent and also my temp probe has been acting funny. Just last night the temp probe read 212 instead of the normal 79.

    Should mention that if i do a power reset the probes will start reading correctly until they freeze again.

    Any suggestions?

    Thanks

  2. #2
    Frequent Contributor zombie's Avatar
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    Check for stray voltage in your tank. A firmware update couldn't hurt and might help.

    Sent from my SM-G935V using Tapatalk

  3. #3
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    No stray voltage. Checked with a multimeter.

    I have not loaded the latest firmware but this was happening before the latest was released.

  4. #4
    Frequent Contributor zombie's Avatar
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    I would update anyway (even if it's just a reload of the version you have installed). 9 out of 10 times a firmware update fixes unexplained problems such as the one you described.

    Sent from my SM-G935V using Tapatalk

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    updated firmware and still having the same issue. frustrating

  6. #6
    Frequent Contributor zombie's Avatar
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    Just thought of something. A short circuit in the temp probe socket or in the temp probe itself will read 212. Remove the temp probe and clean the jack with an air duster and clean the plug with some electrical contact cleaner (coke can work in a pinch) and wipe dry. If it continues the problem after cleaning, either the temp probe is bad and needs to be replaced or less likely there is a hardware problem with the jack itself.

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

  7. #7
    Frequent Visitor bescher's Avatar
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    Quote Originally Posted by swnoob View Post
    No stray voltage. Checked with a multimeter.

    I have not loaded the latest firmware but this was happening before the latest was released.

    For information
    i was to,d that I might have stray voltage, I checked with a MM it was fine on everything
    later that week I got a grounding probe after I installed it my apex amp reading on my EB8 went ballistic. I troubleshoot the problem by removing one plug after another it was a heater. I'm not saying a grounding probe helps everyone but my stray voltage was so low that even the MM didn't pick it up

  8. #8
    Frequent Contributor zombie's Avatar
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    Did you have the multimeter set to AC or DC? Might have missed it because it was set to DC Volts or auto instead of AC.

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

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    Quote Originally Posted by bescher View Post
    For information
    i was to,d that I might have stray voltage, I checked with a MM it was fine on everything
    later that week I got a grounding probe after I installed it my apex amp reading on my EB8 went ballistic. I troubleshoot the problem by removing one plug after another it was a heater. I'm not saying a grounding probe helps everyone but my stray voltage was so low that even the MM didn't pick it up
    Depending on the method of failure, the grounding probe will only alert you to an issue if you have everything plugged into a GFCI. Many times, the leakages result in only milliamps leaking out into the tank. With out a ground probe, the tank acts like a large capacitor and starts to build stray voltage. The ground probe will prevent the stray voltage buildup as the leaking voltage now exits through the house ground. As long as the voltage leaks results in very small current, no harm is noted. However, if you have GFCI outlets, the ground probe will cause an immediate trip.

  10. #10
    Frequent Visitor bigjim's Avatar
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    Does Neptune offer a grounding probe that connects to apex and can send warnings if stray voltage is detected?

    Sent from my SM-G955U using Tapatalk

  11. #11
    Frequent Contributor zombie's Avatar
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    Nope. A grounding probe wouldn't detect that anyway because a grounding probe forces the voltage of the tank to zero.

    One could be made DIY using the ORP port, but I wouldn't recommend doing so unless you have nearly an engineers knowledge of electrical circuits. Doing so safely would require a voltage divider circuit between the tank and ground with a titanium grounding probe with the resistance sized to both reduce wattage through the resistors to below rated value at 120VAC, divide the voltage such that it is detectable and then the signal voltage would need to be limited with a surge arrestor to about 1V to protect the probe port on the apex.

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

  12. #12
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    Quote Originally Posted by zombie View Post
    Nope. A grounding probe wouldn't detect that anyway because a grounding probe forces the voltage of the tank to zero.

    One could be made DIY using the ORP port, but I wouldn't recommend doing so unless you have nearly an engineers knowledge of electrical circuits. Doing so safely would require a voltage divider circuit between the tank and ground with a titanium grounding probe with the resistance sized to both reduce wattage through the resistors to below rated value at 120VAC, divide the voltage such that it is detectable and then the signal voltage would need to be limited with a surge arrestor to about 1V to protect the probe port on the apex.

    You might be an engineer if...You have no life and can prove it mathematically.
    That seems a bit overkill LOL, but it does get me thinking of a way to build an isolated switch for the Apex that would be closed when stray current is detected from the grounding probe. If I had a switch that closed at various times, I could, in theory, note those times and compare them to my equipment log in Apex and determine which device is causing the fault.

  13. #13
    Frequent Visitor bescher's Avatar
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    Quote Originally Posted by zombie View Post
    Did you have the multimeter set to AC or DC? Might have missed it because it was set to DC Volts or auto instead of AC.

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

    No it was set set to ac

    Thanks

  14. #14
    Frequent Visitor bescher's Avatar
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    Quote Originally Posted by clsanchez77 View Post
    Depending on the method of failure, the grounding probe will only alert you to an issue if you have everything plugged into a GFCI. Many times, the leakages result in only milliamps leaking out into the tank. With out a ground probe, the tank acts like a large capacitor and starts to build stray voltage. The ground probe will prevent the stray voltage buildup as the leaking voltage now exits through the house ground. As long as the voltage leaks results in very small current, no harm is noted. However, if you have GFCI outlets, the ground probe will cause an immediate trip.
    I did and donhave everything plugged into a GFCI outlet

  15. #15
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    Quote Originally Posted by bescher View Post
    For information
    i was to,d that I might have stray voltage, I checked with a MM it was fine on everything
    later that week I got a grounding probe after I installed it my apex amp reading on my EB8 went ballistic. I troubleshoot the problem by removing one plug after another it was a heater. I'm not saying a grounding probe helps everyone but my stray voltage was so low that even the MM didn't pick it up
    Quote Originally Posted by bescher View Post
    I did and donhave everything plugged into a GFCI outlet
    I don't think I'm understanding your last statement because it seems to conflict with your first. If you have a ground probe, you cannot have stray voltage..it's immediately grounded. If you have a GFCI, the current that results from the stray voltage would trip the GFCI, in which you would not have the opportunity to test it. I believe the threshold for tripping a GFCI is something on the order of 5 mA, or 0.005A - this is very small.

    In regards to the probes, you clearly have electrical interference. Try straightening the chords so they don't parallel any AC lines or wrap other chords. Then power the unit off and back on again for a good hard restart. I have had to do this anytime installed a new probe. I do wonder why Apex does not shield these cables, there may be a good reason I am not aware of...

  16. #16
    Frequent Contributor zombie's Avatar
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    I don't understand the not shielding part either. For something as sensitive as a conductivity or pH probe, I don't think there is anyone who has the money to buy an apex and conductivity probe that would mind paying 5 more dollars for shielded cables. Could actually be a selling point

    E.g. What puts us apart from the competition...we put accuracy and quality above all else and are proud to be the only aquarium controller that provides shielded cables to protect your readings from electrical interference...

    Could even sell more of them at a higher price point with the right marketing.

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

  17. #17
    Frequent Visitor bescher's Avatar
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    Quote Originally Posted by clsanchez77 View Post
    I don't think I'm understanding your last statement because it seems to conflict with your first. If you have a ground probe, you cannot have stray voltage..it's immediately grounded. If you have a GFCI, the current that results from the stray voltage would trip the GFCI, in which you would not have the opportunity to test it. I believe the threshold for tripping a GFCI is something on the order of 5 mA, or 0.005A - this is very small.

    In regards to the probes, you clearly have electrical interference. Try straightening the chords so they don't parallel any AC lines or wrap other chords. Then power the unit off and back on again for a good hard restart. I have had to do this anytime installed a new probe. I do wonder why Apex does not shield these cables, there may be a good reason I am not aware of...
    I didn't have thevgrounding probe at first. I didn't have it when I tested with the MM. I have had the system on a GFCI since my freshwater days. It wasn't until after installed the probe did I discover the stray voltage coming from a heater

  18. #18
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    OK, that makes a lot more sense lol.

  19. #19
    Frequent Contributor zombie's Avatar
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    Personally I'm not a fan of grounding probes anyway. Unless you add some resistance to the probe even a 5V stray voltage will trip off your tank. When I used them in the past, I would add an inline 15W 1000 ohm resistor so that voltage could stray up to 30V before tripping my 20mA GFCI off.

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

  20. #20
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    Quote Originally Posted by zombie View Post
    Personally I'm not a fan of grounding probes anyway. Unless you add some resistance to the probe even a 5V stray voltage will trip off your tank. When I used them in the past, I would add an inline 15W 1000 ohm resistor so that voltage could stray up to 30V before tripping my 20mA GFCI off.

    You might be an engineer if...You have no life and can prove it mathematically.
    That is not a bad idea at all. Again, if I could figure out how to wire this into a dry contact for the Apex as well, I could then have Apex alert me to a voltage leak before the GFCI trips. If I can log the switch opening/closing and time it with a device, i could troubleshoot the issue without getting my hands wet.

  21. #21
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    Quote Originally Posted by clsanchez77 View Post
    That is not a bad idea at all. Again, if I could figure out how to wire this into a dry contact for the Apex as well, I could then have Apex alert me to a voltage leak before the GFCI trips. If I can log the switch opening/closing and time it with a device, i could troubleshoot the issue without getting my hands wet.
    Use 2 10W 500 ohm resistors in series. Between ground and the midpoint of the two tie that to a solid state or electromechanical relay with a pickup voltage of 10V and a max voltage greater than 120V. Tie the NO contact into a BOB and you have your indication. The only hard part is searching through mouser or digikey to find a relay with the right specs.

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

  22. #22
    Master Control Freak RussM's Avatar
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    Quote Originally Posted by zombie View Post
    A short circuit in the temp probe socket or in the temp probe itself will read 212. .
    Nope... it will be somewhere around 120-122F if shorted.
    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.

  23. #23
    Frequent Contributor zombie's Avatar
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    Quote Originally Posted by RussM View Post
    Nope... it will be somewhere around 120-122F if shorted.
    That makes this a real puzzler then. If a short only reads 120F, then there is no possible way (including stray voltage) that the probe could actually read a value higher than the shorted value.

    Makes me wonder if this is entirely a firmware or internal board problem and has nothing to do with external hardware or the environment.


    OP. I would email support if you haven't already.

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

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