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Thread: Pool Math Calculator

  1. Back To Top    #1

    Join Date
    May 2013
    Location
    New Jersey
    Posts
    176

    Pool Math Calculator

    I never noticed this before, probably because I always used liquid chlorine and thus entered in 12.5% in the calculator when calculating FC, but why does it say "trade" when you enter say 12.5% for example (for FC) in the calculator next to the percentage, but if you enter 8.25% it says "weight."
    7+ years, inground, 25,000 gallon, vinyl, sand filter.

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Pool Math Calculator

    That feature is new this week.

    There are several different standards for measuring the concentration of bleach. Household bleach sold in grocery stores is sold by weight percentage (typically 2% to 8.25%), while liquid chlorine sold by pool stores and cleaning supply stores (typically 10% to 15%) is sold by trade percentage. The two numbers, weight and trade, are fairly close together, but differ just a little because they are based on different historical ways of measuring concentration. I recently updated PoolMath to distinguish between them so it would have better accuracy for higher concentrations of chlorine.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3

    Join Date
    May 2013
    Location
    New Jersey
    Posts
    176

    Re: Pool Math Calculator

    That's what I thought - Thanks for the explanation.
    7+ years, inground, 25,000 gallon, vinyl, sand filter.

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