Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 10 of 10

Thread: Alkalinity wont come down

  1. Back To Top    #1

    Join Date
    Feb 2014
    Location
    oklahoma
    Posts
    45

    Alkalinity wont come down

    i have been to pool store 3 times. each time they say 2 pounds of dry acid. we add and no change or if anything it goes up.
    here is where i am i am not good on pool chemistry so maybe someone can point out something i am not seeing

    FC -2
    Available Chlorine - 2
    Salt - 2600
    calcium -240
    cya - 50
    TA - 430
    PH - 8.0
    acid demand - 6
    no metals in water all else is good

    i have a 17000 gallon fiberglass pool on a sand filter with a salt water generator.

    please help what am i doing wrong.

  2. Back To Top    #2
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,487

    Re: Alkalinity wont come down

    Are you sure TA is that high?

    What is CH?

    Start here: Pool School - ABCs of Pool Water Chemistry

    Then here: Pool School - Lower Total Alkalinity
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  3. Back To Top    #3
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Alkalinity wont come down

    The big problem i see is right here: "i have been to pool store 3 times"

    If (A big if) those numbers are right... it'll take 16 pounds of dry acid just to get pH down to 7.2. That will have the added benefit of reducing TA by... 43. And then over time (assuming no fresh fill water was added) the pH will rise to 7.8 or so and TA will be at 287 so another 13 pounds of dry acid, which will reduce TA by another 34. It'll take a long long time and cost a whole lot of money.

    On the other hand, if you had your own test results in hand and used Muriatic Acid, you could devote a weekend to driving TA down. It will still be in those same steps and it will use a lot of acid, but MA from a big box hardware store has got to be cheaper than dry acid from the pool store and you'll save a lot of trips back and forth. And you'll be in control, not the clerk at the pool store with dollar signs in his eyes.



    And also, your Free Chlorine is too low for your CYA level. Pool School - Chlorine / CYA Chart
    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!

  4. Back To Top    #4

    Join Date
    Feb 2014
    Location
    oklahoma
    Posts
    45

    Re: Alkalinity wont come down

    i have tested TA myself and while my measurements are not super accurate they are close to those of the pool store.

    chlorine is 2.0

    - - - Updated - - -

    calcium hardness is 240

    - - - Updated - - -

    Quote Originally Posted by Richard320 View Post
    The big problem i see is right here: "i have been to pool store 3 times"

    If (A big if) those numbers are right... it'll take 16 pounds of dry acid just to get pH down to 7.2. That will have the added benefit of reducing TA by... 43. And then over time (assuming no fresh fill water was added) the pH will rise to 7.8 or so and TA will be at 287 so another 13 pounds of dry acid, which will reduce TA by another 34. It'll take a long long time and cost a whole lot of money.

    On the other hand, if you had your own test results in hand and used Muriatic Acid, you could devote a weekend to driving TA down. It will still be in those same steps and it will use a lot of acid, but MA from a big box hardware store has got to be cheaper than dry acid from the pool store and you'll save a lot of trips back and forth. And you'll be in control, not the clerk at the pool store with dollar signs in his eyes.



    And also, your Free Chlorine is too low for your CYA level. Pool School - Chlorine / CYA Chart
    why does the pool store keep telling me 2 pounds when it needs 16? is their system nuts?

    i am fine with muriatic but have been told not to put in my fiberglass pool i think i could get away with a bit but seems this much would be an issue or not?

  5. Back To Top    #5
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Alkalinity wont come down

    Quote Originally Posted by rltullis View Post
    i have tested TA myself and while my measurements are not super accurate they are close to those of the pool store.

    chlorine is 2.0

    - - - Updated - - -

    calcium hardness is 240

    - - - Updated - - -



    why does the pool store keep telling me 2 pounds when it needs 16? is their system nuts?

    i am fine with muriatic but have been told not to put in my fiberglass pool i think i could get away with a bit but seems this much would be an issue or not?
    You mix the powder with water and end up with liquid acid before you add, correct? Otherwise you might end up with acid crystals leaving freckles on the pool surface. Why not skip a step and just add liquid acid? Thousands and thousands of TFP members use MA in fiberglass and vinyl with no problems. I suspect pool stores prefer to sell dry acid because it's easier to handle. (For them)
    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!

  6. Back To Top    #6
    Mod Squad kimkats's Avatar
    Join Date
    Jul 2012
    Location
    Tallahassee, FL
    Posts
    26,710

    Re: Alkalinity wont come down

    I bet it costs more also so more $$ for them!

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  7. Back To Top    #7

    Join Date
    Feb 2014
    Location
    oklahoma
    Posts
    45

    Re: Alkalinity wont come down

    so how much muriatic acid are we talking about here to get this where it needs to be? also how in the world did it get this high? I just opened the pool, have not done much other than clean it out.

  8. Back To Top    #8
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Alkalinity wont come down

    Quote Originally Posted by rltullis View Post
    so how much muriatic acid are we talking about here to get this where it needs to be? also how in the world did it get this high? I just opened the pool, have not done much other than clean it out.
    Gallons and gallons.

    High TA can come from fill water, someone adding too much Baking Soda, or testing errors.
    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!

  9. Back To Top    #9

    Join Date
    Feb 2014
    Location
    oklahoma
    Posts
    45

    Re: Alkalinity wont come down

    i have been told by several folks that our local water is being treated differently this year. maybe that is the cause.

  10. Back To Top    #10
    Mod Squad kimkats's Avatar
    Join Date
    Jul 2012
    Location
    Tallahassee, FL
    Posts
    26,710

    Re: Alkalinity wont come down

    I would do a test on your fill water just to see what you have ahead of you.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •