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Thread: Shock advice

  1. Back To Top    #1

    Join Date
    Jun 2016
    Location
    Orange County, CA
    Posts
    2

    Shock advice

    Greetings everyone,

    I started taking care of my ancient plaster pool about a month ago, and according to my test kit it's time for the pool to be shocked. I've never done this before, but according to http://www.freepoolcalculator.com I need to add about 240 fl. oz. of 8.25% bleach in order to shock the pool...

    I know that many chemicals shouldn't be added to the water all at once, but is this true for bleach when shocking the pool? Put differently, should I add all 240 oz. of bleach at the same time?

    Thanks, and sorry for the noob question!!
    -----------------------------
    17,500 gallon plaster pool from the Pleistocene epoch :P
    Hayward cartridge filter

  2. Back To Top    #2
    ckk81's Avatar
    Join Date
    Jan 2015
    Location
    Kalamazoo MI
    Posts
    232

    Re: Shock advice

    Hi!
    What test kit are you using? Please post a full panel of results.

    We don't shock we SLAM.
    Read up on Pool School.
    Pool School - Pool School
    30K? gal (20x40, 3ft shallow to 8-9ft hopper), Vinyl IG, single speed 1HP pump, Hayward Micro Clear DE-3600 filter, Hayward Aqua Rite SWG T15 Cell, Rheem/Raypack M206A heater

  3. Back To Top    #3
    Mod Squad zea3's Avatar
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    Jul 2009
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    Houston, Texas
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    9,200

    Re: Shock advice

    Hi, welcome to TFP! The whole point of applying a "shock" to the pool was to have a rapid increase in FC, so normally you would put in all the chlorine that was required to raise the FC to shock levels at one time. Whether or not 240 ounces is right for your pool or not I can't say without a complete set of test results, or at least knowing what your current CYA level is.

    I have some recommended reading for you:
    ABCs of Pool Water Chemistry
    SLAM
    FC/CYA Chart

    We also have a free pool calculator, PoolMath . It will tell you how much of each chemical you need to add based on your test results, and there is a feature at the bottom, Effects of adding chemicals, that will show you how adding chemicals will change the water chemistry.
    TFP Moderator
    Helpful links: TF Test Kits,TFP Pool School, PoolMath
    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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  4. Back To Top    #4

    Join Date
    Jun 2016
    Location
    Orange County, CA
    Posts
    2

    Re: Shock advice

    Thanks for the responses! I'm using the LaMotte ColorQ Pro test kit, which tells me that the free chlorine is 4.8 and the total chlorine is 6.7, hence my belief that a shock would be appropriate. With CYA at 35, the shock requirements tool at freepoolcalculator.com suggests that I add 243 oz. of 8.25% bleach (which I can get at Target). From what I can tell, the PoolMath tool suggests that I should target a free chlorine level of about 14 when shocking the pool, given my current chemical levels. The PoolMath tool also tells me that adding 243 oz. of 8.25% bleach will raise my free chlorine by 9.2, and since 9.2 + 4.8 = 14, it seems that both the freepoolcalculator.com and PoolMath tools are giving me the same advice.

    At least now I now that I should add all of the bleach at the same time!
    -----------------------------
    17,500 gallon plaster pool from the Pleistocene epoch :P
    Hayward cartridge filter

  5. Back To Top    #5
    ckk81's Avatar
    Join Date
    Jan 2015
    Location
    Kalamazoo MI
    Posts
    232

    Re: Shock advice

    You do need a SLAM according to protocol around here. Follow the directions and you'll be on your way. I'm not sure how well regarded your test kit is I'll let others comment on that.

    30K? gal (20x40, 3ft shallow to 8-9ft hopper), Vinyl IG, single speed 1HP pump, Hayward Micro Clear DE-3600 filter, Hayward Aqua Rite SWG T15 Cell, Rheem/Raypack M206A heater

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