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Thread: How does a SWG work?

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    How does a SWG work?

    Is there a web site that definitively explains how a SWG works?

    Not a marketing site!

    One that explains what happens to the sodium.
    -Steve, Westford, MA; 31,326 gal 21' x 41' IG Imperial 1000 Series vinyl pool
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    dmanb2b's Avatar
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    Re: How does a SWG work?

    The chlorine generator works through a process called electrolysis. Inside the chlorine generator, there is an electrolytic cell. This cell contains layers of plates that are electrically charged. Plugging the chlorine generator into an electrical source generates this electric charge.


    The direct current produced by the chlorine generator then passes through the water, which contains the added salt, or sodium chloride (NaCl). The negative chloride ions (Cl-) each lose one electron during this process. The electron then attaches to the positive electrode that is passing through the water. The electrode and the chloride electron are then released as a chlorine gas (Cl2).

    The positive hydrogen ions (H+) from the water (H2O) then receive an electron from the negative electrode. The hydrogen and electron pair together and form a hydrogen gas. Sodium ions (Na+) and a hydroxide ion ( OH- ) are all that remain in the water.

    When the chlorine that was created finishes purifying the water, it becomes salt and water once more. This s al t is then continuously reused. Therefore, more salt does not need to be added to the water because of this process. It does, however, need to be occasionally added because of salt loss caused by splash out, overflow, bather drag off, or filter backwash.
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    Re: How does a SWG work?

    Quote Originally Posted by dmanb2b
    The positive hydrogen ions (H+) from the water (H2O) then receive an electron from the negative electrode. The hydrogen and electron pair together and form a hydrogen gas. Sodium ions (Na+) and a hydroxide ion ( OH- ) are all that remain in the water.
    Yes, but "Sodium hydroxide (NaOH), also known as lye and caustic soda, is a caustic metallic base".

    Isn't that a bit harmful to equipment and people?

    You might say the levels are very low. But I was told that the reason the SWG works is that in the cell the levels of chlorine are at shock levels, even though the levels of chlorine in the pool are lower than in a manually chlorinated pool.

    If the chlorine levels are high in the cell then so too would the NaOH be high.
    -Steve, Westford, MA; 31,326 gal 21' x 41' IG Imperial 1000 Series vinyl pool
    96 gpm Hayward DE-4800 filter,1.5HP,3hrs/day,$0.72/hr;TF100 test kit, Borate & Salt strips

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    spishex's Avatar
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    Re: How does a SWG work?

    It leaves sodium ions in the water, the same as adding sodium hypochlorite. I don't think the sodium has any role in the electrolytic reaction so you're not generating lye on a continuous basis. Sodium as an ion is found at levels up to 3000ppm in bottled water, roughly comparable to a SWG-equipped pool. Here's some reading from Oregon DHS on Sodium, and here's Richard's explanation of how a SWG works vs. manually dosing.

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    dmanb2b's Avatar
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    Re: How does a SWG work?

    thank you spish....SWGs have been in use 30+ years, have yet to hear of someone being ill effected from lye poisioning.
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    New2Me's Avatar
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    Re: How does a SWG work?

    If the chlorine levels are high in the cell then so too would the NaOH be high.
    Isn't that a bit harmful to equipment and people?
    I would strongly suggest keeping people and equipment out of the cell.
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    pool4me's Avatar
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    Re: How does a SWG work?


    I would strongly suggest keeping people and equipment out of the cell.


    Well thanks, very much you Buzz-Kill. I just invited a few hot ladies over to the house to hang out in the cell. You really have to squeeze in there but .... wow , the fun!

    Cozy.....
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