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Thread: Test tube measures consistent?

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    kjdiver's Avatar
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    Test tube measures consistent?

    I have bought several tests, replacement tests, and obviously the TFP test kit...all through TFP. I now have 5 test tubes with ml measurements on the side. Of the 5, 3 are equal measurements when I fill it with 25ml. The 25ml poured into the other 2 tubes are closer to 30ml.

    1. Am I crazy?
    2. What tubes do I use??? How screwed up have my tests been for the last 2 years?
    3. Shouldn't all the test tubes be labeled accurately?
    3. Kinda feeling crazy!

    Thanks!
    Learning since 10/01/2008 --> 32,000 gallon free form, Unknown old 1 hp pump, Pentair Sand Filter, Raypak Heater

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    Re: Test tube measures consistent?

    See if you can get your hands on a syringe. A 10 ml syringe would be useful in helping you determine which tube's measurements are closest to being correct.

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    Mod Squad Bama Rambler's Avatar
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    Re: Test tube measures consistent?

    I use a 10ml syringe and never worry about the markings on the vials. I'd love to get a 25 or 30 ml syringe but haven't found one so far.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Test tube measures consistent?

    Class-A volumetric flasks are available in 25 mL sizes however you can't really use them for titrations and such, but they contain precisely 25 mL.
    You have different types of labware, "To Dispense" and "To Contain". (Flasks are "To Contain" or "To Dispense", empty one in a Taylor 9198 and observe that the 9198 is bang on).
    It also helps to view the meniscus behind a white card inscribed with a dark line.
    Best is to weigh the water, 25 mL weighs 25 grams.

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    Re: Test tube measures consistent?

    I'm in the medical field and have access to 60 ml blunt tip syringes. These are great because I take a sample from the pool and can get a PH and FC test with it. I use a 20 ml syringe for the CYA test. It would be great if these syringes could be included in the TF-100 to help people get more accurate results.
    3500 gallon 14x42 Intex Ultra Frame
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    Re: Test tube measures consistent?

    Quote Originally Posted by Bama Rambler
    I use a 10ml syringe and never worry about the markings on the vials. I'd love to get a 25 or 30 ml syringe but haven't found one so far.
    http://www.allegromedical.com/syringes- ... 91862.html

    $17.81 for a box of 40, or $1.00 each.

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    Mod Squad Bama Rambler's Avatar
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    Re: Test tube measures consistent?

    Yeah but with shipping of $8.95 that's 10 bucks for one. And that's all I need. Maybe what I should have said, was I haven't found one at a reasonable enough price to actually buy one.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Test tube measures consistent?

    I would think that a local medical supply place would have the 30 ml available.

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