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Thread: We Don't Understand...

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    We Don't Understand...

    We don't understand Suggested FC Levels on the Pool Calculator.

    I'm not sure which problem to address first...

    our numbers for tonight...FC - 2.5
    CC - .5
    TC - 3
    PH - 7.5
    TA - 160
    CH - 190
    CYA - 40
    Temp - 82

    We, of course know we have chlorine to add tonight. But should we shock???? And if so, how do we figure out how much chlorine to add?

    P.S. We've added 9 oz. of Muriatic Acid for the last two nights. jenn
    ABG, Cornelius, 12'x24', oval, 7,700 gals, 1 1/2 hp Hayward pump, sand filter. BBB. 6-4'x10' Fafco solar panels, permanently installed on wooden ground rack, GL235 auto controller.

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    Re: We Don't Understand...

    Quote Originally Posted by jj
    We don't understand Suggested FC Levels on the Pool Calculator.

    I'm not sure which problem to address first...

    our numbers for tonight...FC - 2.5
    CC - .5
    TC - 3
    PH - 7.5
    TA - 160
    CH - 190
    CYA - 40
    Temp - 82

    We, of course know we have chlorine to add tonight. But should we shock???? And if so, how do we figure out how much chlorine to add?

    P.S. We've added 9 oz. of Muriatic Acid for the last two nights. jenn
    Jenn,

    I really like chemgeek's 3 criteria he mentions frequently

    1. Very Clear Water - Do you have that?
    2. CC's of .5 or less - you've got that
    3. The ability to hold FC with not more than 1ppm overnight loss - Can you do that?

    If you can meet those, there is no need to shock your pool.

    Use Jasonlions nice calculator found in any of his posts to calculate how much chlorine you need for your size pool to maintain the FC level around 3-6ppm on a continual basis.

    If you find you can't meet all three above, then I would suggest shocking up to 15ppm and, when you meet all three, let the chlorine drift back down to the 3-6ppm maintenance level.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Join Date
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    New Jersey
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    Hi,

    Well to let us help you further what size pool do you have? gallons? what type of pool? do you use bleach to add chlorine currently? Is your pool cloudy? algae? etc?

    The pool calculator will tell you how much chlorine you need to have to raise your FC from what is currently is (2.5) to whatever number you desire. This will give you the amount of 6% bleach to add (6% is the store purchased laundry bleach).

    The CYA/FC calculator will give you your shock level for a pool in relation to CYA reading. I have a CYA level of 40 also so my shock level is 16 but higher if you have mustard algae.

    Post your pool gallons and other info and I sure someone here will get you right on track.

    Ls
    14 x 32 Fiberglass Pool 10K gal. Hayward Pump and Sand Filter. Autopilot SWG Dig 48 and Heat Siphon 3.25sx Heat Pump.

    The Pool Calculator
    Chlorine/CYA Chart by Chemgeek

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    yeah i can read...lol...a 25 x 54 pool...what are the depths of the pool? That will also help us determine how many gallons.
    14 x 32 Fiberglass Pool 10K gal. Hayward Pump and Sand Filter. Autopilot SWG Dig 48 and Heat Siphon 3.25sx Heat Pump.

    The Pool Calculator
    Chlorine/CYA Chart by Chemgeek

  5. Back To Top    #5
    Yes, we held 2.5 overnight.
    I just now filled out the sig, hope it is what's needed. Let me know if I'm missing something.

    Ls...see we don't know what that means when you say your shock level is 16. It said ours was 15...what the heck does that mean? jenn
    ABG, Cornelius, 12'x24', oval, 7,700 gals, 1 1/2 hp Hayward pump, sand filter. BBB. 6-4'x10' Fafco solar panels, permanently installed on wooden ground rack, GL235 auto controller.

  6. Back To Top    #6

    Oh Dave...

    I should have said ...'no, we don't have very ckear water. jenn
    ABG, Cornelius, 12'x24', oval, 7,700 gals, 1 1/2 hp Hayward pump, sand filter. BBB. 6-4'x10' Fafco solar panels, permanently installed on wooden ground rack, GL235 auto controller.

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    Re: Oh Dave...

    Quote Originally Posted by jj
    I should have said ...'no, we don't have very ckear water. jenn
    Then I would shock the pool.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  8. Back To Top    #8

    Join Date
    May 2007
    Location
    New Jersey
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    98
    The shock level is the level that you want to bring your FC reading up to and be able to hold it overnight. Bring you FC up to 15-16 from your current 2.5. That is what is referring to the "shock level". So basically if you need to shock that will be your level based on your CYA reading. Most in this forum like to add bleach as the shock since it is straight chlorine and doesnt add any other chemicals. That is where the pool calc will tell you how much you need to purchase to reach your recommended shock level from your current reading. Add bleach over a return with pump running and run pump for at least 24 hours. After adding bleach wait about 2 hours and retest the water. Then retest the water in the morning and see if it held. If not bring it back up to shock level until it holds overnight for you. You want to run the pump/filter until the water clears and your FC is holding overnight. Hope that helps clarify it for you.

    Ls
    14 x 32 Fiberglass Pool 10K gal. Hayward Pump and Sand Filter. Autopilot SWG Dig 48 and Heat Siphon 3.25sx Heat Pump.

    The Pool Calculator
    Chlorine/CYA Chart by Chemgeek

  9. Back To Top    #9
    You won't believe this, or maybe you will...the little light bulb that hadn't come on until I read this was...take the recommended target shock level 15 and put it in the goal box on the left hand side to come up with the dang answer on the Calculator!

    We would be lost without this forum. My thanks....jenn
    ABG, Cornelius, 12'x24', oval, 7,700 gals, 1 1/2 hp Hayward pump, sand filter. BBB. 6-4'x10' Fafco solar panels, permanently installed on wooden ground rack, GL235 auto controller.

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