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Thread: What is the ph of rain ?

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    What is the ph of rain ?

    What is the ph of rain ?

    Other related questions:
    My pool ph is a little high, about 7.9 - 8.0. Will it gradually go up or down over the winter as rain water is added to it?
    I just tested my tap water and it has a very high. Is this normal?
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

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    UnderWaterVanya's Avatar
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    Re: What is the ph of rain ?

    Quote Originally Posted by TomAtlanta
    What is the ph of rain ?

    Other related questions:
    My pool ph is a little high, about 7.9 - 8.0. Will it gradually go up or down over the winter as rain water is added to it?
    I just tested my tap water and it has a very high. Is this normal?
    Tap water pH in my area is above 8. This is intentional per the water department in order to reduce corrosion.
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

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    dmanb2b's Avatar
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    Re: What is the ph of rain ?

    I'm extra lucky...in addition to high PH my TA is 330+. It all depends. Post up a set of results, before closing....ph near 8 is too high IMO to rely on acidic rain to do the lowering...even if the rain is slightly acidic, rain aerates your water as well which raises PH. Typical showers tend to be a neutral PH event.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

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    Re: What is the ph of rain ?

    Post up a set of results,
    Will do in a few days. I haven't done a total test in a while, but will do it and post before this weekend.
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

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    Re: What is the ph of rain ?

    The pH of rain is generally acidic due to the dissolved carbon dioxide (carbonic acid) from the air as well as from other acidic sources (nitric and sulfuric acids). However, the TA (pH buffering) of rain is fairly low so the effect of rain on pool pH is minimal from the rain itself (unless it is very, very acidic). Generally, rain increases aeration of the pool water so will raise the pH of the water as a result.

    If you dilute the pool with a lot of rain water, but don't have it splash into the pool, then the pH will likely drop slowly. If you let the raindrops splash into the pool, then the pH may go up at first and then slowly drop if there is enough dilution of the water.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: What is the ph of rain ?

    @chem - You explain things so clearly... that I even get it.

    Thanks for that.
    Helen
    Helen
    Dallas Area, 16,000 gal IG, Easytouch 8 computer, Intelliflo 3HP Variable Speed pool pump, Pentair Smart Pump 4x160, Pentair 3/4 HP Booster Pump, FNS 60 DE 60, Mastertemp 400, Rainbow 320, Dual Timer w/ freeze protection, Intellichor SWG, TF100 Test Kit, POOL FILLED AUG 3, 2012, ORDER YOUR TF100 KIT FROM http://tftestkits.net
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    In the Industry

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    Re: What is the ph of rain ?

    Courtesy of Wikipedia,

    The pH of rain varies, especially due to its origin. On Americas East Coast, rain that is derived from the Atlantic Ocean typically has a pH of 5.0-5.6; rain that comes across the continental from the west has a pH of 3.8-4.8; and local thunderstorms can have a pH as low as 2.0.[70] Rain becomes acidic primarily due to the presence of two strong acids, sulfuric acid (H2SO4) and nitric acid (HNO3). Sulfuric acid is derived from natural sources such as volcanoes, and wetlands (sulfate reducing bacteria); and anthropogenic sources such as the combustion of fossil fuels, and mining where H2S is present. Nitric acid is produced by natural sources such as lightning, soil bacteria, and natural fires; while also produced anthropogenically by the combustion of fossil fuels and from power plants. In the past 20 years the concentrations of nitric and sulfuric acid has decreased in presence of rainwater, which may be due to the significant increase in ammonium (most likely as ammonia from livestock production), which acts as a buffer in acid rain and raising the pH.[71]

    70 Joan D. Willey (1988-01). "Effect of storm type on rainwater composition in southeastern North Carolina". Environmental Science & Technology.
    71 Joan D. Willey (2006-08-19). "Changing Chemical Composition of Precipitation in Wilmington, North Carolina, U.S.A.: Implications for the Continental U.S.A". Environmental Science & Technology.

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