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Thread: PH during shock process

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    PH during shock process

    Using bleach to shock, I would think that during the shock process the PH would jump up pretty ridiculously. But, as the FC comes back to normal levles, so would the PH. So, during the shock process, should you just ignore PH? Or will a very high PH harm anything for that short period of time?
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    Christian's Avatar
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    Re: PH during shock process

    Drop your pH to 7.1 or 7.2 prior to shocking then ignore it until the shock process is complete.

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    Mod Squad Bama Rambler's Avatar
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    Re: PH during shock process

    As C said, lower the pH prior to shock and don't worry about it till you're done. The problem is that the pH tests are wrong above about 10 ppm FC so testing it during shocking is going to provide you with inaccurate results.
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    Re: PH during shock process

    Got it. Thanks, guys.
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    elwood58's Avatar
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    Re: PH during shock process

    The reason for dropping pH prior to shock process is actually two reasons:

    1. pH is going to go up, up up
    2. pH readings after you start shocking will not be accurate.
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    UnderWaterVanya's Avatar
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    Re: PH during shock process

    Quote Originally Posted by elwood58
    The reason for dropping pH prior to shock process is actually two reasons:

    1. pH is going to go up, up up
    2. pH readings after you start shocking will not be accurate.
    Is this accurate? I thought from what I read the pH value will show falsely high at FC > 10. So it isn't about an actual pH that's sky high as much as one you cannot accurately test - right?

    Also there is another reason that was reported here - that the Chlorine works better at lower pH - is that also true or did I misunderstand?
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    Mod Squad jblizzle's Avatar
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    Re: PH during shock process

    I think the confusion I have seen pop up a few times is that adding bleach with temporarily raise the pH, but as it is consumed the pH will drop again making the bleach almost pH neutral. You are correct that the pH will read falsely high at FC > 10ppm ... and worse as the FC gets even higher (thus the pH should not be adjusted with high FC). I think these 2 things work to cause confusion.

    I think you are also correct that the FC is more effective at lower pH.
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