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Thread: Understanding rates of change

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    Understanding rates of change

    Hi, my second post. I am slowly getting comfortable however a few questions remain.

    1. I have a plaster pool, but CH level is extremely high, probably around 900+. is this disastrous or not? I guess lowering would only be possible by emptying the pool, and then the replacement water would need to be softer.

    2. I have a TA of 60, but my pH wants to sit at around 8 to 8.2 naturally. I add muriatic acid very couple of days to get to 7.5 but it just goes straight back up. Anything I can do to prevent that? I have a high amount of aeration, as we have a waterfall from the spa to the pool all day when pump runs (10 hours a day). I also notice very small air bubbles in 2 of the 4 inlet jets over the last couple weeks. Solving that doesn't seem too easy.

    3. While I'm asking questions, is it typical to have all the flow through the 2 skimmer baskets and none from the bottom of the pool. I have automatic valves and it seems they were set that way.

    Any help appreciated!
    Pool size ~ 14000 gallons, in-ground plaster, Jandy AqualinkRS salt water generator, cartridge filter, Pump TBC - in Houston Texas

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    Re: Understanding rates of change

    900 ppm CH is manageable. Just keep your CSI between -0.3 and +0.3.

    For example,

    pH 7.6
    TA 50
    CH 900
    CYA 60
    Salt 3200
    Temp 94 F

    Results in a CSI of 0.04. Keep your CYA between 60 to 80 ppm. Let your TA go down a little bit if that keeps the pH more stable.

    calc.html

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    BoDarville's Avatar
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    Re: Understanding rates of change

    Quote Originally Posted by Nico24
    1. I have a plaster pool, but CH level is extremely high, probably around 900+. is this disastrous or not? I guess lowering would only be possible by emptying the pool, and then the replacement water would need to be softer.
    Managing pH and TA to keep Calcite Saturation Index (CSI) slightly negative is the key. Check out this post from one of our Expert members on managing scale with a CH level in the 800's - 900's: Progress on scale

    Quote Originally Posted by Nico24
    2. I have a TA of 60, but my pH wants to sit at around 8 to 8.2 naturally. I add muriatic acid very couple of days to get to 7.5 but it just goes straight back up. Anything I can do to prevent that? I have a high amount of aeration, as we have a waterfall from the spa to the pool all day when pump runs (10 hours a day). I also notice very small air bubbles in 2 of the 4 inlet jets over the last couple weeks. Solving that doesn't seem too easy.
    I would try turning some of the aeration features off before lowering TA any further. Also, the bubbles coming from the inlets indicate an air leak. One quick thing to check is the gasket on the pump cover. Others may chime in with other ideas on what else to check.

    Quote Originally Posted by Nico24
    3. While I'm asking questions, is it typical to have all the flow through the 2 skimmer baskets and none from the bottom of the pool. I have automatic valves and it seems they were set that way.
    You should have some flow through the main drain as well to provide more even circulation. I would think (and hope) there is a way to override the automatic valve settings.
    Gold Supporter, TFP Lifetime Supporter, 26,680 gal Plaster IGP 3.5 - 10' depth / Attached Waterfall Spa, Manually Chlorinated, Triton Sand Filter, 1.5 HP * 1.1 SF = 1.65 SFHP 1-speed Pentair WhisperFlo WF-26 Pump, 400K BTU NG Teledyne Laars Series One Heater, Polaris 360, Test Kit Comparison, Chlorine/CYA Chart, SLAMing Your Pool, OCLT
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