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Thread: CSI. Help me understand it.

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    CSI. Help me understand it.

    I can't figure out csi. Mine on poolmath is -0.19. Can someone shed some light on this for me please?
    30k Gallons, IG plaster, Jacuzzi Sand Storm 350lb Sand filter, 1hp Jacuzzi Magnum Force pump. Taylor K-2006 kit. Jacuzzi J-D300 side suction vac.

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    Re: CSI. Help me understand it.

    The experts will chime in soon, but my understanding is that you want your CSI anywhere between -0.3 and 0.3. Yours is in that range right now so that it good!

    CSI below -0.6 means your water is likely to leach calcium out of your plaster causing pitting on your pool surface, and CSI above 0.6 means your water is likely to start depositing calcium scale on your pool surface.

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    Mod Squad pooldv's Avatar
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    Re: CSI. Help me understand it.



    Right on all counts.

    Some light reading for the weekend
    Pool School - Calcium Scaling
    Langelier and Calcite Saturation Indices (LSI and CSI)
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    Re: CSI. Help me understand it.

    While CH tells you how much calcium is in the water, the CSI tells you if it will stay in the water or (if CSI is high) precipitate out as scale on pool surfaces. If CSI too low it will cause the water to actually dissolve the calcium out of the plaster and grout, damaging the pool.
    chiefwej
    Tucson, AZ
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    Re: CSI. Help me understand it.

    I am not a big csi fan. It can be a helpful tool but it is also irrelevant in most cases.

    CSI measures the "tendancy" for a pool to precipitate calcium. It doesn't mean you will, it means you are in a zone where you may need some adjustments to prevent calcium scale.

    The caveat is two-fold....

    1. If you have a vinyl liner pool, it can most always be ignored.

    2. Importantly, if you stay within the guidelines we test for at TFP, you can ignore csi once again.

    Certainly, there can be a precious few outliers wherein CSI gives you a better picture of your pool water management. Many people like to use it as a backup and there is certainly nothing wrong with that.

    Do the calcs for it if you wish but staying within the parameters set forth in "The ABC's of Pool Water Chemistry" up in Pool School, will accomplish almost the same thing.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad pooldv's Avatar
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    Re: CSI. Help me understand it.

    Agreed, if you can maintain your water within the Recommended Levels then CSI takes care of itself. The water supply in some areas makes that very difficult with either high CH or high TA or both. CSI offers an ability to manage outside the box when you can't drain your water every month to keep CH under 500 or add enough acid and aeration to lower your TA below 120, etc.

    I'm not sure about the water supply in your area. The water in the lakes in OK is a lot nicer than the water in the lakes in TX, I know that for sure. Dallas water has a strong tendency to scale with high alkalinity and high CH during droughts.
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    Re: CSI. Help me understand it.

    Arizona seems to be the worse for water conditions that are "outside the box"

    We are already sinking just a little from all the Snowbirds so we wont be able to take many Arizonans.

    (I suppose we may have to take a few....as long as they don't say, "here's how we used to do it up North) JK JK
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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