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Thread: Impact of rain on water balance

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    Impact of rain on water balance

    What impact, if any, does rain have on FC, pH and TA?
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    AnnaK's Avatar
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    Re: Impact of rain on water balance

    Depends on the kind of rain you're getting. A gentle, steady 'farmers' rain' won't have much impact. The sort of gully washers we've been having here in eastern PA are increasing my pH as a result of aeration. TA has remained steady at 90, pH rose from 7.6 to 7.8 overnight. We had 4" of rain within an hour. You can imagine how that pounded the water surface.
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    Re: Impact of rain on water balance

    AnnaK makes a great point.....it depends.

    I believe the size of your pool is significant as well. A 2" rain into a 36" ABG will have more impact than the same rain on a large pool with a deep diving end.

    By far, the greatest impact is if your decking does not drain the pool properly and runoff is allowed to enter the pool.....that is usually very big trouble.
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    Re: Impact of rain on water balance

    The sort of gully washers we've been having here in eastern PA are increasing my pH as a result of aeration. TA has remained steady at 90, pH rose from 7.6 to 7.8 overnight. We had 4" of rain within an hour. You can imagine how that pounded the water surface.
    You are not kidding AnnaK, I've been dumping water every other day (and my pH is also on the rise.)

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    Re: Impact of rain on water balance

    I thought rain was acidic, thereby reducing pH....but then the raindrops aerate the water, thereby increasing pH...so it would basically be a wash (no pun intended) for the most part. Is any of this assumption correct?
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    Re: Impact of rain on water balance

    A heavy rain on an uncovered pool will aerate a lot, enough to counteract the acidic rain. Gentler rain and covers limit this effect and you might see a drop. I didn't get my cover until after the major rains were over so I don't have any personal experience to back that up, however.
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