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Thread: Sample size?

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    Sample size?

    I just purchased my TF-100 test kit and ran my first set of tests. I have question that I wasn't sure of a good way to search for, so forgive me if it's been asked before.

    In running my tests, I retrieved the appropriate sample size from the pool and retreated to the shady porch table to complete the test, washed the test tube and stirrer bar in the kitchen sink, and then returned to the pool to get the appropriate sample size for the next test, repeat, repeat.

    My question is, can a get a larger sample of pool water, say a pint or so, in a clean jar and use this water to refill the test tube with for each new test, or will time in the jar skew the results?

    One larger sample would save a bunch of running back and forth, but not a good idea if it jeopardizes the test results.


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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Sample size?

    Welcome to TFP!

    Getting a cup (or half cup) of water and then using it for all of the tests is fine. Just make sure that you do the FC/CC test first and PH second. Those two tests can be affected by the sample sitting out for several minutes (or longer). The remaining tests can be done more slowly without problems.

    I like to use a small squirt bottle to hold the water sample. That makes it really easy to fill the vials with exactly the right amount of pool water.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Sample size?

    Thanks for the reply. The squirt bottle is a great idea!

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    ahampleman's Avatar
    Join Date
    Nov 2011
    Ocala, FL

    Re: Sample size?

    I use the bottle the pool store gave me. .
    21,500 gallon outdoor in-ground 16'x32' Diamond Brite Cool Blue pool. Sta-Rite SuperMax 1.5 HP 2 speed pump running on low for 8 hrs a day, Sta-rite PCX125 cartridge filter, CircuPool RJ-45 SWG, 500 watt incandesce light, 1 skimmer, 4 returns, Dolphin Oasis Z5 robot cleaner, Solar-Breeze NX & TF-100 test kit, Taylor K1766 kit with speed stir.

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    Re: Sample size?

    I use a tiny plastic pitcher and a 10cc syringe I swiped from the gazillion we throw out around here that are donated to our medical mission we do every year.

    Rob B
    My $100 pool finally died after 6 years.
    Totally got our monies worth!
    Butterfly made me do it...

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    Isaac-1's Avatar
    Join Date
    May 2010
    SW Louisiana

    Re: Sample size?

    I use an old small plastic measuring cup with a pouring notch on the side I think it is 4 or 6 oz the markings wore off years ago, it is easy to clean.

    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    gboulton's Avatar
    Join Date
    Apr 2012
    Nashville, TN

    Re: Sample size?

    Quote Originally Posted by JasonLion
    I like to use a small squirt bottle to hold the water sample. That makes it really easy to fill the vials with exactly the right amount of pool water.
    Man...the simplest ideas are the coolest.
    Pool School helps me maintain my 13,500G 24' x 48" ASP with Sand Filtration using a TF100 Test Kit and Pool Calculator.
    Remember, the Shock Process should be followed until : 1. CC is less than 0.5 ppm, 2. An OCLT shows a loss of 1.0 ppm or less and, 3. The water is crystal clear.
    --I didn't buy my pool to swim in it. I bought my pool to watch my wife swim in it. :wink:

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    Join Date
    Mar 2010
    Spring, TX

    Re: Sample size?

    Quote Originally Posted by ahampleman
    I use the bottle the pool store gave me. .
    +1. Just go to your local pool store and ask for a bottle to bring a sample back in and you can grab one or two. Sometimes I like to fill two if I am doing a complete test of all the test. This way I can rinse out my testing tubes with pool water to avoid any mixing of regular tap water vs pool water.
    13,000 Plaster IG Pool approx
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