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Thread: Cannot seem to lower alkalinity in my pool

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    Join Date
    May 2016
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    Murrieta/CA
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    Cannot seem to lower alkalinity in my pool

    Good afternoon.

    I am hoping that someone can help me figure out why I cannot seem to get my alkalinity down to the recommended level (80 to 120)

    My pool is a 10000 gallon, I am running a Hayward DE filter. My pump runs for 3 hours at 90% and 2.5 hours at 30%. I run a liquid chlorinator to add my liquid chlorine. My pool is in the sun from about 10 am until the sun goes down.

    I was able to get my Alkalinity down some but just wont stay there. Originally it was at 220 ppm and I added muriatic acid to lower it. I was able to get it lowered to 160 ppm last night but tonight when I checked it is now back up to 190 ppm. Nothing has been added except my liquid chlorine.


    My test results are as followed.

    Chlorine - 5 ppm
    PH - between 7.8 and 8.2 think it is closer to 8.2 but hard to tell.
    Calcium - yes present
    Hardness - 300 pp
    Alkalinity - 190 ppm
    CYA - 50

    any sugguestions?

    Scott
    Pool Rectangle with attached Spa (approx. 8000 gal, depths 4 feet and 5-1/2 feet), Pump - Hayward Super II, Filter - Hayward Micro Filter DE Model 4800.

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    Join Date
    Dec 2014
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    Santa Ana, CA
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    Re: Cannot seem to lower alkalinity in my pool

    Quote Originally Posted by SoCalNewPoolOwner View Post
    Good afternoon.

    I am hoping that someone can help me figure out why I cannot seem to get my alkalinity down to the recommended level (80 to 120)

    My pool is a 10000 gallon, I am running a Hayward DE filter. My pump runs for 3 hours at 90% and 2.5 hours at 30%. I run a liquid chlorinator to add my liquid chlorine. My pool is in the sun from about 10 am until the sun goes down.

    I was able to get my Alkalinity down some but just wont stay there. Originally it was at 220 ppm and I added muriatic acid to lower it. I was able to get it lowered to 160 ppm last night but tonight when I checked it is now back up to 190 ppm. Nothing has been added except my liquid chlorine.


    My test results are as followed.

    Chlorine - 5 ppm
    PH - between 7.8 and 8.2 think it is closer to 8.2 but hard to tell.
    Calcium - yes present
    Hardness - 300 pp
    Alkalinity - 190 ppm
    CYA - 50

    any sugguestions?

    Scott
    assuming you used one of recommended test kits to get those numbers I'd lower you pH to 7.2 and leave TA alone for now- it tends to drop over time on its own when you keep lowering pH. You just need to find 'sweet' spot for TA so your pH remains stable. pH is the primary parameter you should monitor regularly. what is the material of your liner? If plaster- how old? New plaster tends to drive pH up for at least a year.
    44k plaster pool, Pentair 011018 pump, DE6020 filter, LED lights, K2006 test kit

  3. Back To Top    #3

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    May 2016
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    Murrieta/CA
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    Re: Cannot seem to lower alkalinity in my pool

    Quote Originally Posted by max2k View Post
    assuming you used one of recommended test kits to get those numbers I'd lower you pH to 7.2 and leave TA alone for now- it tends to drop over time on its own when you keep lowering pH. You just need to find 'sweet' spot for TA so your pH remains stable. pH is the primary parameter you should monitor regularly. what is the material of your liner? If plaster- how old? New plaster tends to drive pH up for at least a year.

    Hi Max2K, Yes I have one of the test kits from the Pool School. My liner is plaster but my pool is 12 years old. Ok I will lower my PH to 7.2 and see if over time if that will lower the TA. Thanks for the help.

    Scott
    Pool Rectangle with attached Spa (approx. 8000 gal, depths 4 feet and 5-1/2 feet), Pump - Hayward Super II, Filter - Hayward Micro Filter DE Model 4800.

  4. Back To Top    #4

    Join Date
    Dec 2014
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    Santa Ana, CA
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    523

    Re: Cannot seem to lower alkalinity in my pool

    Quote Originally Posted by SoCalNewPoolOwner View Post
    Hi Max2K, Yes I have one of the test kits from the Pool School. My liner is plaster but my pool is 12 years old. Ok I will lower my PH to 7.2 and see if over time if that will lower the TA. Thanks for the help.

    Scott
    it did for me- I wasn't looking at TA for about a year (not recommended) and kept adding MA as pH was creeping up. Eventually it reached the point where the same doze of MA would drive pH down below 6.8 quite suddenly. Then I tested for TA and found it was 40 so I had to bring it up to 70 with baking soda and now pH doesn't jump around. I'm adding about half of MA volume I used to add and doing that less frequently. It actually surprises me when it doesn't move anywhere for entire week, this never happened before.
    44k plaster pool, Pentair 011018 pump, DE6020 filter, LED lights, K2006 test kit

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    Mod Squad pooldv's Avatar
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    Re: Cannot seem to lower alkalinity in my pool

    Here is the process for lowering TA, Pool School - Lower Total Alkalinity
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    Re: Cannot seem to lower alkalinity in my pool

    Quote Originally Posted by max2k View Post
    it did for me- I wasn't looking at TA for about a year (not recommended) and kept adding MA as pH was creeping up. Eventually it reached the point where the same doze of MA would drive pH down below 6.8 quite suddenly. Then I tested for TA and found it was 40 so I had to bring it up to 70 with baking soda and now pH doesn't jump around. I'm adding about half of MA volume I used to add and doing that less frequently. It actually surprises me when it doesn't move anywhere for entire week, this never happened before.
    \


    Thanks for the info Max2K. I just added my reducer for PH and will see what happens now.

    - - - Updated - - -

    Quote Originally Posted by pooldv View Post
    Here is the process for lowering TA, Pool School - Lower Total Alkalinity
    thanks Pooldv for the info
    Pool Rectangle with attached Spa (approx. 8000 gal, depths 4 feet and 5-1/2 feet), Pump - Hayward Super II, Filter - Hayward Micro Filter DE Model 4800.

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