Automated Alkalinity Measurement

Discussion in 'DIY' started by rygh, Jan 27, 2015.

  1. rygh

    rygh Supporting Member

    So as part of designing my water-exchange system, I was thinking about Alk, and
    that it might be possible to integrate a simple ALK measurement device.
    There were others interested, so here it is.

    This is NOT something that does fancy automated titration, and gives you a dKH number.
    (Although I do have some ideas on that also)
    This is simpler. It really just tells you if your ALK has deviated much from a set level.
    But that is what you really need most of the time anyway.

    And a BIG caveat: I have not built and tested it yet, and might never do it. It may not work at all.

    The design is attached as a PDF.

    Water exchange thread here:

    Attached Files:

    jonmos75 likes this.
  2. rygh

    rygh Supporting Member

    Comments welcome, especially if you see a problem.
  3. tygunn

    tygunn Webmaster

    I'm definitely interested in this. So have you figured out the ranges of error at the various stages to get an idea of roughly how close the number you get will be to actual?
  4. rygh

    rygh Supporting Member

    I have not experimented yet, no.
    Main error causes:

    * PH probe drift
    Minimal, since we can compensate by using the first measurement.

    * Inconsistency in Acid solution
    Might need to shake that occasionally.

    * Inconsistency in amount of Acid solution added
    Peristaltic pumps are decent, but far from exact.

    * CO2 effects
    Not sure about that one.

    * Non-linear PH/Alk curves
    If we are not in a fairly and steep part of the curve, a small error can throw
    the measurement off quite a bit.

    I have a lot of things ahead of this in my to-do list, so it will be a while.
  5. Ranjib Dey

    Ranjib Dey Webmaster

    Resurrecting this thread :0)
    @rygh Is this still operational?
  6. rygh

    rygh Supporting Member

    Never really got it going.

    Did a few measurements and things, then work+family got in the way.
    I do think it would work for "tracking" Alk, and telling me if it drifts, but not something
    good enough to actually measure the value.

    And now it looks like real measurement tools are finally making it to market.

    But another recent thread on R2R did get me interested a bit again, so who knows.
    I am wondering if it is a coincidence that you are resurrecting this.
  7. scuzy

    scuzy Supporting Member

    Just get one of the already avail solutuon :)

    Sent from my iPhone using Tapatalk Pro
  8. Ranjib Dey

    Ranjib Dey Webmaster

    No its not coincidence. I came here chasing down that thread :0-)

    I had pondered about a more generic version of that, semi-automatic titration system. I'll get to it sometime in future. The r2r thread is important as the author has mentioned making it opensource, if that happens, whatever comes out of that project can be useful.
  9. rygh

    rygh Supporting Member

    Or send water out every couple months to be Triton tested.
    At $25 per test, 4 times per year, that is 10 years worth for the same $1000 as a tester.
    And you get all sorts of results, not just Alk.
    A bit of a different application though.
  10. scuzy

    scuzy Supporting Member

    That's 4 alk readings compare to 90 days x 8 readings a day. S lot could change in 90 days.

    Sent from my iPhone using Tapatalk Pro
  11. Ranjib Dey

    Ranjib Dey Webmaster

    Triton does not give alk values
  12. Flagg37

    Flagg37 Colorado member

    Right, triton doesn’t but the icp testing that @rygh did performs an extra test for it and includes it with the results. The triton test also doesn’t cost $25/test like the other icp test does.
    Ranjib Dey likes this.
  13. rygh

    rygh Supporting Member

    Yes, meant ICP.
    Ranjib Dey likes this.

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