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Thread: Testing Calcium

  1. Back To Top    #1

    Join Date
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    Testing Calcium

    In previous posts readers have been advised in testing calcium that you need to keep swirling the vial for 20 to 30 seconds to mix thoroughly between drops. If your calcium level is near 300 ppm then the test would require 10 to 15 minutes. Are there any valid means to speed up the test and still achieve accurate results?

    For example, can you quickly mix the first 20 drops since you know your pool calcium level has consistently tested above 200 and pool calcium levels do not change quickly?

    If you do not mix thoroughly does the calcium test give results that are too low, too high, or just plain unpredictable?
    30,000 gallon gunite in-ground with a spillover spa, Diving board and water slide
    Hayward 1 HP Super II filter pump, Hayward 24 " Sand Filter Pro Series using zeolite media
    Polaris 380 cleaner with ¾ HP booster pump, Hayward Heatmaster pool heater, AutoPilot DIG-220 Power Supply SC-60 cell
    Testing with the TF-100 Test Kit

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    donaldm823's Avatar
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    Re: Testing Calcium

    you can buy a magentic stirrer to speed up the mixing. I bought one last year and it works great-I do not pause between drops and get accurate results.

    Here is where I bought mine:
    http://piscines-apollo.com/english_stirrer.htm
    Don SW Florida
    10,000 gal in ground concrete pool
    Pentair Cartridge filter, Pentair SWG, Pentair Intelliflow VS pump (11018)
    FAFCO solar panels w/Pentair SolarTouch controller
    using BBB for pool chemistry/Lamotte ColorQ tester for daily testing

  3. Back To Top    #3

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    Re: Testing Calcium

    Steve, you can do the 'multiple drops at a time' method without problems If I know the CH is going to be 300+, I'll do 20 drops, swirl for 30 sec then 5 and swirl, 5 and swirl,, then do a drop or 2 at a time...If you get the endpoint after adding multiple drops, you may have overshot the mark You can either repeat the test and not add as many drops at a time when you get close or, if you are doing 2 at a time, just accept that you could be off by 20ppm 8)
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  4. Back To Top    #4
    Guest

    Re: Testing Calcium

    Quote Originally Posted by waste
    Steve, you can do the 'multiple drops at a time' method without problems If I know the CH is going to be 300+, I'll do 20 drops, swirl for 30 sec then 5 and swirl, 5 and swirl,, then do a drop or 2 at a time...If you get the endpoint after adding multiple drops, you may have overshot the mark You can either repeat the test and not add as many drops at a time when you get close or, if you are doing 2 at a time, just accept that you could be off by 20ppm 8)
    Ted, actually it can create some problems. If there are any metals present adding the EDTA titrant too quickly is a sure recipe for a 'floating endpoint' .
    a better way if you know you have a very high CH would be to use a 10 ml sample, 10 drops of calcium buffer, 3 drops of indicator, and then when you titrate each drop of titrant is equivalent ot 25 ppm CH It's a lower resolution test but if your CH above 300-350 ppm it's really all the precision you need.

    Also, it is possible to get results that are too high if you do not mix well after each drop. Often, when you take the time to do the test right you find that your CH was not anywhere near as high as you thought.
    The only preactical way I have found to speed up the test without getting inaccurate results is with a magnetic stirrer.

  5. Back To Top    #5

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    Re: Testing Calcium

    Evan

    (BAD WASTE )
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  6. Back To Top    #6
    Guest

    Re: Testing Calcium

    Quote Originally Posted by waste
    Evan

    (BAD WASTE )
    Guess I have to take you out back and beat you with that backwash hose again!

  7. Back To Top    #7

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    Re: Testing Calcium

    Quote Originally Posted by waterbear
    Quote Originally Posted by waste
    Evan

    (BAD WASTE )
    Guess I have to take you out back and beat you with that backwash hose again!


    ONLY if one of us dresses like the pic in this thread
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  8. Back To Top    #8
    Guest

    Re: Testing Calcium

    Quote Originally Posted by waste
    Quote Originally Posted by waterbear
    Quote Originally Posted by waste
    Evan

    (BAD WASTE )
    Guess I have to take you out back and beat you with that backwash hose again!


    ONLY if one of us dresses like the pic in this thread
    Now you are scaring me!
    (anyway, I don't think they have that in my size!)

  9. Back To Top    #9
    Guest

    Re: Testing Calcium

    Steve456,
    Sorry about the thread hijack... we now return to your regularly scheduled programming...

    I believe you will find your question has been answered.
    FYI, I have one of the magnetic stirrers that was linked above and it's what I use!
    http://piscines-apollo.com/english_stirrer.htm
    The seller is one of our members and has a great product, IMHO.

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