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Thread: High total alkalinity

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    High total alkalinity

    I am trying to get my total alkalinity to come down. It is 320-340. My ph has been staying around 7.2. Chlorine is high. FC is 7. Ideas on what to do to lower the alkalinity?
    Laura
    Baltimore MD
    IG pool 25,000 gallons
    Cartridge filter
    Plaster pool

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    Mod Squad JVTrain's Avatar
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    Re: High total alkalinity

    Adding acid is the only way to lower alkalinity. Increase aeration to raise pH, then add more acid to bring down to 7 to 7.2.

    I'm surprised your pH is stable (not rising quickly) at that high TA.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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    Re: High total alkalinity

    TA 320-340 is astronomical. Are you sure? Have you done your OWN testing?

    If accurate, I can't see any rational hope other than draining.... a LOT of water....

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    Re: High total alkalinity

    I've tested with the TF 100 kit. Today's reading is 300, ph still at 7.2 and FC at 7. I'm thinking it was because I had drained a great deal of water out of the pool at the beginning of the season and brought the water level back up by using rain water..(we had significant rain over several days). not really wanting to drain again.
    Laura
    Baltimore MD
    IG pool 25,000 gallons
    Cartridge filter
    Plaster pool

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    Mod Squad JVTrain's Avatar
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    Re: High total alkalinity

    Rain water TA is VERY low unless the rain was collected in a way that could have exposed it to alkalinity. Rain water refill should be the best way to replace high TA water.

    No sense draining. Check out your CSI by inputting all your numbers into Pool Math. If at your current levels, your CSI is in the scaling range, then you should try to actively lower the TA and maintain a lower pH until it comes down. Aeration/acid addition is the fastest way to lower TA. See here: Pool School - Lower Total Alkalinity
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: High total alkalinity

    Are you sure you don't have static electricity on your dropper tip? Wipe the dropper tip with a moist cloth to be sure. The drops you count in the TA test should be well-formed hanging drops and you should hold the bottle upright. Unless your pool is covered most of the time, it would be unusual for the pH to be low when the TA is high unless you were using acidic chemicals such as Trichlor, non-chlorine shock (MPS) or even Dichlor (which is net acidic when accounting for chlorine usage/consumption).
    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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    Re: High total alkalinity

    Did you need to drain and refill due to high CYA?

    What is your current CYA?

    What is the TA of your tap water?

    Do you use trichlor 3" chlorine tabs?

    What is your calcium hardness?

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