Results 1 to 12 of 12

Thread: Conductivity probe issue

  1. #1
    Regular Vistor
    Join Date
    Apr 2015
    Location
    United Kingdom
    Posts
    21

    Conductivity probe issue

    Hi,

    I recently recalibrated my conductivity probe and after this it was reading exactly the same as my refractometer. Calibration was done as per the guidelines.

    Temperate is stable and it has it's own temperature probe that is next to the conductivity probe.

    The day after calibration the reading started drifting up from the initial 34.7 to 36. Today it has so far risen to 40.5 and appears to be continuing to rise.

    There has been no temperature change and the refractometer continues to show the same measurement of a fraction under 35.

    Any ideas?

  2. #2
    Frequent Contributor zombie's Avatar
    Join Date
    Dec 2013
    Location
    Denver, CO
    Posts
    13,176
    If it's a new probe that initial drift is expected. If not, it could be bubbles or significant electrical interference by something else close to it's cord.

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

  3. #3
    Regular Vistor
    Join Date
    Apr 2015
    Location
    United Kingdom
    Posts
    21
    Quote Originally Posted by zombie View Post
    If it's a new probe that initial drift is expected. If not, it could be bubbles or significant electrical interference by something else close to it's cord.

    You might be an engineer if...You have no life and can prove it mathematically.
    Thanks for the reply.

    It isn't a new probe.

    There is an algae reactor next to it but the reading has been rising all day and the light has not been turned on and the pump is nowhere near it (not even in the same compartment). Nothing where the probe is located has changed. It always showed a high reading but I used it to show a change rather than get an exact reading. I recalibrated and it was showing the correct reading, but after one day started drifting up and hasn't stopped yet.

    I could try to route the cable away from other cables but, as you will know, it's quite astonishing how many cables you end up with and not always easy to avoid!

    It is now reading 42.7 and still climbing...

  4. #4
    Regular Vistor
    Join Date
    Apr 2015
    Location
    United Kingdom
    Posts
    21
    I recalibrated the probe in the tank - not using the calibration solution - and so far it looks to be holding steady and giving the correct reading when compared to my calibrated refractometer. We'll see how long it lasts...

  5. #5
    New User
    Join Date
    Mar 2018
    Location
    Minneapolis
    Posts
    10
    This is a massive issue for us newbies and often difficult to troubleshoot. I am still working on mine after a week. What would be nice is if there were an option to tell the Apex what your tank is at and leave it at that. Hint Hint:

  6. #6
    New User
    Join Date
    Feb 2018
    Location
    UK
    Posts
    5
    iv had my new apex running now two weeks and mine is all over the place. feel like giving it up and sending it back to the shop

  7. #7
    Frequent Contributor zombie's Avatar
    Join Date
    Dec 2013
    Location
    Denver, CO
    Posts
    13,176
    Quote Originally Posted by johnboy9877 View Post
    iv had my new apex running now two weeks and mine is all over the place. feel like giving it up and sending it back to the shop
    They are touchy. If the reading is changing a lot throughout the day that is usually because temp compensation isn't enabled. If the average magnitude of the reading is off, it needs to be recalibrated and you need to make certain that the packet matches tank temp exactly. The other thing to keep in mind is that it can take between 12 hrs to a week for the probe to "settle in" and give consistent measurements (mine was 90% there in 12 hrs and 100% There in 4 days). Almost every single issue I have seen with conductivity relates to one of those three things.

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

  8. #8
    Regular Vistor
    Join Date
    Apr 2015
    Location
    United Kingdom
    Posts
    21
    Quote Originally Posted by zombie View Post
    They are touchy. If the reading is changing a lot throughout the day that is usually because temp compensation isn't enabled. If the average magnitude of the reading is off, it needs to be recalibrated and you need to make certain that the packet matches tank temp exactly. The other thing to keep in mind is that it can take between 12 hrs to a week for the probe to "settle in" and give consistent measurements (mine was 90% there in 12 hrs and 100% There in 4 days). Almost every single issue I have seen with conductivity relates to one of those three things.

    You might be an engineer if...You have no life and can prove it mathematically.
    That all sounds logical but the only thing that has kept mine showing an accurate reading for more than two days is calibrating it using the tank water in the same position where it has always been placed.

  9. #9
    New User
    Join Date
    Mar 2018
    Location
    Minneapolis, MN
    Posts
    3
    When you say "something else close", how close are you talking? My return chamber is about the end 6 inches of my 20 long custom sump. My probes are in the same chamber about as far away as they can be from my reactor and return pumps but still a few inches away. Is this too close to ever get a good reading? Should I move my probes to the opposite side filter sock/refugium chamber? Any concern with having the probes under the grow light in the refugium or near the growing chaeto? Also, all the cords run out of the same side of my stand to a cabinet that houses my EB832 and Apex unit (2016). How far apart should the probe cables be kept from power cords? I'm thinking I may have to mount the Apex unit on the other side of my stand than where the power cords leave to keep probe cables from the power cords. Can interference be brought in from an aquabus cable if I need to run one from my equipment cabinet where the EB832 is and the Apex unit under the stand? This would be the only cord I can't keep away from the probe cables. Thanks!

  10. #10
    Frequent Contributor zombie's Avatar
    Join Date
    Dec 2013
    Location
    Denver, CO
    Posts
    13,176
    Within 2 inches of a magnetic source (return pump, parallel power wire, transformer, etc) is "too close". Any further and the magnetic interference decays enough to make the effect neglegable.

    Do be cognizant of stray voltage though as that can also have an effect. You can check this with a multimeter between the ground of an outlet and the tank itself. More than a few volts can sometimes cause problems.

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

  11. #11
    Regular Vistor
    Join Date
    Apr 2015
    Location
    United Kingdom
    Posts
    21
    I find it odd that it's always drift up to the maximum when I have calibrated using the solution but it seems to have held it's accurate reading after just calibrating it in the sump with the system's water. Nothing has changed in terms of position or other nearby equipment.

    Weird.

  12. #12
    New User
    Join Date
    Mar 2018
    Location
    Minneapolis, MN
    Posts
    3
    Thanks! Since when installing the probes I had to make sure that the probes weren't touching the pumps, I'm pretty sure they're too close. I also get spikes in my pH reading whenever my pumps stop or kick on. I'll be moving my Apex into my stand so the probe cables don't have to follow the same path as the power cords from stand to equipment cabinet and also moving the probes to a different sump chamber.

Similar Threads

  1. Apex Conductivity Probe setup issue
    By ShaneD in forum AquaBus Modules, Probes, and Breakout Boxes
    Replies: 0
    Last Post: 03-27-2021, 09:36
  2. Help conductivity probe issue
    By ibrat82 in forum AquaBus Modules, Probes, and Breakout Boxes
    Replies: 24
    Last Post: 05-16-2016, 19:29
  3. Yet another conductivity probe issue
    By gdesanto in forum AquaBus Modules, Probes, and Breakout Boxes
    Replies: 0
    Last Post: 04-19-2016, 16:17
  4. Conductivity Probe Issue
    By Jduck in forum AquaBus Modules, Probes, and Breakout Boxes
    Replies: 2
    Last Post: 12-11-2015, 18:20
  5. Conductivity probe issue
    By Reefman in forum AquaBus Modules, Probes, and Breakout Boxes
    Replies: 0
    Last Post: 10-25-2013, 10:58

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •