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Thread: Is it better to drain or treat?

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    Post Is it better to drain or treat?

    May I ask why it is better to treat than drain?
    ~Paul
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    BoDarville's Avatar
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    Re: Hello new friends!

    Quote Originally Posted by Jabooh1
    May I ask why it is better to treat than drain?
    There's really no one right answer to this question. A couple of factors to consider include pool size (i.e., water volume), cost of replacement water, water restrictions that may exist, fill water source (municipal or well), and the water chemistry (in particular CYA and metals) along with any other afflictions that are impacting the pool. Generally speaking, if there is an algae outbreak in a small pool (less than 5,000 gallons), it may be cheaper and quicker to drain & refill the pool as opposed to treating the existing water.

    In a larger pool, a few other factors come into play. Let's say there was an algae outbreak in a pool my size (~27K gallons). If the CYA was in-range (less than 80 ppm), it would be better to treat it using the SLAM Process. OTOH, if the CYA was 200 ppm, a partial or series of partial drain & refills would be better since the only way to lower the CYA level is by water replacement. Even after doing that, you still may need to treat the water to kill off any remaining algae.

    Then there's metals. If the water in a pool has a high metal content and the problem was caused by the owner/operator (for example, by using copper-based algaecides), then it would be better to drain & refill the pool, provided the owner has access to municipal water and stops using copper-based algaecides and other products that could add metals to the water. In contrast, a pool owner whose fill water comes from a well is usually better off treating their water since well water almost always contains some metals thereby rendering a drain/refill pointless.

    These are just a few scenarios to consider. Each case should be evaluated individually based on several factors and is one of the reasons we ask for such things as pool information, general location, test results, fill water source, and chemicals/products used.

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    Divin Dave's Avatar
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    Re: Is it better to drain or treat?

    And for some parts of the country, its a possiblity for the pool to pop out of the ground due to hydrostatic pressure.
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    Divin Dave,
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    Re: Is it better to drain or treat?

    Interesting. I guess I never considered treating a bad pool. In Houston it cost me $120 to fill my 18k gal pool on city water.
    ~Paul
    19x40 IG including 10' BE, 18,000 gal, plaster, 48 SF DE, 1.5HP pump, AquaPure SWCG, Ozonejoe 30MR, Rockwaterfall, LED light, TF-100 Fill date 11/21/2014
    My ODK Build | My Pool Build | If You're From Texas Vote Here

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    JasonLion's Avatar
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    Re: Is it better to drain or treat?

    One rule of thumb about this is that if you have an above ground pool of 5,000 gallons or less it is almost always worth dumping the water and starting over, and otherwise you are better treating the pool. However, as others have already mentioned, there are many factors that come into the decision. For a larger pool, 15,000+ gallons, it is nearly always better to treat the water.

    Some other factors that haven't been mentioned: If you replace the water you will at a minimum need to add CYA, and probably balance some other levels as well, which adds to the expense. In-ground vinyl liner pools and fiberglass pools can be damaged if drained completely. Replacing water is no guarantee of getting rid of algae, which will sometimes/often come right back as soon as the pool is full again. And so on.
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    Re: Is it better to drain or treat?

    Mine would definitely be treat, as I don't want to replace the borates, salt, and cya.

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