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Thread: Testing bleach for chlorine concentration

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    Join Date
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    Testing bleach for chlorine concentration

    Just in case you want to confirm you're getting 6% bleach or want to test the stuff you've had setting around, can a given amount of bleach be diluted with non-chlorinated water and then tested for its chlorine content? Is it even feasible since we're talking diluting 60,000 ppm to something readable in the 0-20 ppm range? If so how, what proportions would you use?
    18X36 IG vinyl 22100 gal. 1.0 HP Hayward Pump w/300# Hayward sand filter.

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    JasonLion's Avatar
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    Re: Testing bleach for chlorine concentration

    If you do a 100 to 1 dilution twice the FC measurement in ppm of that will equal the actual % of the original bleach. The procedure is a little tricky to do with enough precision to be useful (watch out for contamination in the second dilution), but most people can manage it with a little care and patience.

    The other approach is to put it in your pool and see how much it affects your FC level.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Testing bleach for chlorine concentration

    Quote Originally Posted by JasonLion

    The other approach is to put it in your pool and see how much it affects your FC level.
    This is what I did. I expected a rise of 5ppm on a gallon and a half but got 7 instead. According to the calculator for my size pool this would be 8% at 192oz. This was the "Basic" brand from my local grocery store. (Kroger)
    I normally use 12% from the pool store as it's cheaper but getting ready to go out of town and wanted to give my wife a smaller jug to pour from than the 5 gallon jug the 12% comes in.
    27' round AG vinyl, 54" height with 18,200 gallons of water.
    1HP pump, 150lb sand filter run 12-14 per day. Using 12.5% liquid chlorine. BBB method.
    Taylor K-2006 test kit. Lamotte strips for borate at 50ppm.
    Goals: CYA-40, TA-80, FC-4, CC-0, Borate-50, PH-7.4-7.8 with use of fountain.

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    Re: Testing bleach for chlorine concentration

    Quote Originally Posted by gsmornot
    I expected a rise of 5ppm on a gallon and a half but got 7 instead.
    For a 27' round 4' deep I get 17000 gallons, not 18,200. But that still doesn't explain all the difference; 1.5 gal of 6% would be about 5.5, not 7.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

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    Re: Testing bleach for chlorine concentration

    Close. My pool is 54" tall and the water stays nearly to the top of the skimmer. Just above the top side screws. Still, it may be close to 17,000 but its not what the calculator says.

    The 5ppm number came from the pool calculator. Adding Chlorox brand I did see about 5ppm for the same volume as the non-brand-name stuff that gave me 7ppm.
    27' round AG vinyl, 54" height with 18,200 gallons of water.
    1HP pump, 150lb sand filter run 12-14 per day. Using 12.5% liquid chlorine. BBB method.
    Taylor K-2006 test kit. Lamotte strips for borate at 50ppm.
    Goals: CYA-40, TA-80, FC-4, CC-0, Borate-50, PH-7.4-7.8 with use of fountain.

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