PH Pen recommendations?

Discussion in 'General Planted Tank Discussions' started by 5678, 21 Oct 2015.

  1. 5678

    5678 Member

    Messages:
    340
    Location:
    South Oxfordshire
    Looking for something reliable that will hold it's calibration for at least a few months before needing to be checked.

    Suggestions?
     
  2. stu_

    stu_ Member

    Messages:
    555
    Location:
    Gloucester
  3. alto

    alto Member

    Messages:
    4,436
    Hanna Instruments has always targeted this market with reasonable priced/reasonable performance pH monitoring products.

    Regardless of claims, you should check your calibration weekly, choose a standard or reference solution that is close to your measuring pH (of interest), make sure this is used & stored correctly (ie dispense a small volume to check your probe, then discard; never place the electrode directly into your reference or calibration standard bottles, you can purchase single use envelopes of references/standards).
    It's recommended to use a reference solution that is NOT one of your calibration points, eg if using pH 7 & pH 10 as calibration solutions, choose a pH 8 as your reference check.
    Actual calibration may only need to be done occasionally.

    Depending on what you do with the sensor membrane & how this impacts the internal reference, any pH pen/probe can last a good (or short) while.
    The sensor part of a pH monitor can range in cost from a few dollars to hundreds of dollars, same goes for the electronic component - those sold for the aquarium trade are a dull, stolid lot & hold up well to abuse ;)
    - in exchange the pH measured is around 6.2 (precision & accuracy are the compromise, most of these sort work well in harder water, not so well in soft water ... add 100mM NaCl or KCl & they perform to specification)

    (note that electronic calibration does not check pH sensor performance, it's meant as a back up check or refinement to solution calibration)
     
    dw1305 and 5678 like this.
  4. 5678

    5678 Member

    Messages:
    340
    Location:
    South Oxfordshire
  5. alto

    alto Member

    Messages:
    4,436
    It's a decent kit, especially as the electrode is replaceable BUT check for price & availability (useful to know if there's a 6-8 week back order).

    You don't actually need a temperature sensor at the pH's & temps we usually run aquaria at, so try to find a cheaper version without this (sometimes it makes no difference)

    This one is no where near as nice but will suffice.

    Also price shop, often times, there are offers to be had through distributors/retailers rather than Hanna Inst direct (HI will match but rather depends on how much they've gone into direct sales)

    Also try to buy one that has an auto-shut-off feature as they usually run on specialized batteries (with significant markup)

    Those buffer solutions are good quality, again price/delivery shop, look for kit details eg, pH monitor + solutions package.

    BUT I'll also state that though I've done all this monitoring in the past, now I just observe plants & livestock.
    OTOH if you're going to invest in tech, then I feel it's important to understand it's limitations especially in terms of calibration & assumed performance durability & delivery :)
     
  6. Andy Thurston

    Andy Thurston Forum Moderator Staff Member

    Messages:
    2,819
    Greenfinger2, Ryan Thang To and 5678 like this.

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