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Thread: Does calcium hardness stop climbing?

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    Does calcium hardness stop climbing?

    Hello!

    I live in a hard water area with high heat, so draining in the summer isn't a good option. I'm managing the potential scaling by keeping my pH at 7.5 or below. However, my TF test kit shows that my CH level has remained at approx. 1200 for the last three months. Is this possible? Does calcium hardness plateau?

    Thanks for the assist!

    CH 1200
    TA 110
    pH 7.5
    TC 11
    CC 0
    FC 11
    CYA 120
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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    Richard320's Avatar
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    Jan 2010
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    San Dimas, CA (LA County)
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    Re: Does calcium hardness stop climbing?

    No, CH keeps climbing with evaporation. Calcium and water arrive together. Water evaporates, Calcium does not.

    However, if you've been backwashing a lot, it could seem flat. With your cartridge filter, that seems unlikely. More likely is that the CH is coming out of suspension and sticking to the walls. Do you see any light greyish/tan blotches anywhere? They'd be more noticeable when the pool is shaded or the sky is overcast and disappear when it's bright. That's scale.

    With CYA 120, your minimum FC should stay above 9 at all times. If algae gets a start, it will be almost impossible to kill it with CYA that high. It's a tough pill to swallow, especially this year, but have you considered replacing some water? That would lower both CYA and CH.
    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!

  3. Back To Top    #3

    Re: Does calcium hardness stop climbing?

    Geez Richard, with you being the hard water king I was hoping for some better news

    I won't have a chance to drain for a few more weeks....it's already 105 and I'm always nervous about cracking the plaster in this heat.
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

  4. Back To Top    #4

    Re: Does calcium hardness stop climbing?

    Quote Originally Posted by Richard320 View Post
    No, CH keeps climbing with evaporation..... More likely is that the CH is coming out of suspension and sticking to the walls. Do you see any light greyish/tan blotches anywhere? They'd be more noticeable when the pool is shaded or the sky is overcast and disappear when it's bright. That's scale.
    Yep, that's exactly what has happened. Since acid washing last year, I have kept my pH below 7.5 at all times. Thought I was safe, but....
    Perhaps it's a function of super-saturation? If so, the magic number for my pool is 1200.....another tough lesson learned
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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