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Thread: Pool Calculator says -0.49 CSI, should I add calcium?

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    Join Date
    Oct 2010
    Location
    Fulton, MD
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    24

    Pool Calculator says -0.49 CSI, should I add calcium?

    Opened the pool a week and a half ago, here are my test results:

    FC 8.5
    CC 0.5 (maybe 0, not sure)
    pH 7.4
    T/A 80
    CH 220
    CYA 60
    temp 59

    Pool calculator returns a CSI of -0.49. Do I need to add calcium? Also, if the CC increases further, do I need to shock if we're not yet swimming? Anything else to watch out for?

    Thanks.
    14,000 gal. in-ground white plaster, 24" Crystal Flo Sand Filter, automatic cleaner, Laars Lite 2 400K BTU Heater

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    Join Date
    Mar 2007
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    San Rafael, CA USA
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    12,082

    Re: Pool Calculator says -0.49 CSI, should I add calcium?

    For now, I'd just raise the pH to 7.7. As the water warms up, the pH should drop down some. Yes, you could bump up the CH if you plan on keeping the TA where it is, but you can do that later when the water warms up if you want to.
    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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    Richard320's Avatar
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    Jan 2010
    Location
    San Dimas, CA (LA County)
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    Re: Pool Calculator says -0.49 CSI, should I add calcium?

    That depends....

    I have been keeping my pool in the -.5 to-.6 zone for a few months, in order to dissolve some ugly calcium scale. It's slow, but it does seem to be working.
    So, if you have any scaling, I'd leave things alone.

    On the other hand, if you have a new finish, it will likely drive things up by itself. But if it's not new, but looks like it is, then I'd probably want to give it a little nudge towards zero.

    Have you tested your fill water? Because water will evaporate, but Calcium is forever. Soon as things heat up, your CH will start rising, unless there's a bunch of kids splashing 4" water out every day.

    Play around with pool calculator. See what happens when the temperature goes up, and how much of what you'd need to add. You're not technically in the danger zone, but if 2 bucks worth of increaser gives you peace of mind, spend it. Or maybe $20... Only you know what it's worth to you.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Join Date
    Oct 2010
    Location
    Fulton, MD
    Posts
    24

    Re: Pool Calculator says -0.49 CSI, should I add calcium?

    Thanks for the suggestions.

    The pool is about 12 years old (we've been in the house less than a year though). Our well water is quite soft. The pool was drained down about 12-14 inches upon close, and rain/snow over the winter filled it up by the time we opened, so it makes sense that the calcium is down compared to last fall. Our neighbor who also has a pool commented that he has to add calcium every year (although I'm not going to go only by what he says, since he relies on the local pool store that uses strips for testing, and this is the same guy who suggested I save on electricity by not opening the pool so early, "just do like I do, pour in some algaecide through the mesh cover, spray the cover off with the hose, and open when the water hits swimming temps".)
    14,000 gal. in-ground white plaster, 24" Crystal Flo Sand Filter, automatic cleaner, Laars Lite 2 400K BTU Heater

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