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Thread: Stubborn Alkalinity

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    Stubborn Alkalinity

    I decided to add borates to my pool water and step #1 is to get alkalinity down. My alkalinity has always been a little (~120) high and normally I don't worry too much about it.

    I tested on Thursday and my pH was 8 and alkalinity was 110. I added a gallon of muratic acid and retested Friday and pH dropped to 7.5 and alkalinity dropped to 100. I added another gallon of acid and retested last night. pH went down to 7.2 and alkalinity was still at 100. I just tested this morning and pH is back up to 7.5 and alkalinity is back up to 120. I've been leaving the pool running 24x7 to increase agitation.

    Am I doing something wrong?
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

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    Richard320's Avatar
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    Re: Stubborn Alkalinity

    Either you're introducing more TA via refill water or you're testing wrong. You don't happen to have an autofill, do you? As far as testing error, static electricity on the tip of the R-009 reagent is a known issue. It makes the drops smaller than they should be and gives you falsely high readings. Wiping the tip with a damp paper towel between drops will eliminate it.
    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.
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    Divin Dave's Avatar
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    Oct 2013
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    Longview, Texas
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    Re: Stubborn Alkalinity

    Hi,
    you arent doing anything wrong.
    Lowering the TA using MA and then aerating for pH can take several days or more.

    Regarding your TA test result, I suspect there might be a drop or 2 testing error. When adding the regeant, hold the bottle straight up and down.
    If the regent is fairly new, use a damp cloth to wipe the dropper on the bottle between each drop. With new regent, static electricity can effect the drop size and using a damp rag on the dropper eliminates that.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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    Re: Stubborn Alkalinity

    Quote Originally Posted by Richard320 View Post
    Either you're introducing more TA via refill water or you're testing wrong. You don't happen to have an autofill, do you? As far as testing error, static electricity on the tip of the R-009 reagent is a known issue. It makes the drops smaller than they should be and gives you falsely high readings. Wiping the tip with a damp paper towel between drops will eliminate it.
    No refills in the past 2 days. No autofill. I wipe the tip with a wet paper towel after each drop as the instructions say. I'll add more acid and keep on testing.

    Follow up: Running the pump 24x7 does speed up the process, right? I don't mind doing it but don't want to waste the electricity if it's not worth it. Thanks for the feedback!
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

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    Re: Stubborn Alkalinity

    Can you post the ingredients from the label on the acid bottle?

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    Re: Stubborn Alkalinity

    Quote Originally Posted by JamesW View Post
    Can you post the ingredients from the label on the acid bottle?
    It's 31.45% muriatic acid. It's doing it's job dropping pH so I know it's working.
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

  7. Back To Top    #7

    Re: Stubborn Alkalinity

    You started with a ta of 110 and added 2 gallons of acid which should have dropped the ta to about 60. It doesn't make sense that it's at 120 now. What else have you added?

  8. Back To Top    #8

    Re: Stubborn Alkalinity

    Quote Originally Posted by JamesW View Post
    You started with a ta of 110 and added 2 gallons of acid which should have dropped the ta to about 60. It doesn't make sense that it's at 120 now. What else have you added?
    I added a little CYA and Calcium on Thursday since my niece and nephew accidentally drained a few thousand gallons last weekend. How do you calculate Alkalinity drop? I should also add that my water is crazy high in carbonate hardness (27 degrees).
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

  9. Back To Top    #9

    Re: Stubborn Alkalinity

    Use "Effects of adding chemicals" in pool math.

    What is the TA of your fill water?

  10. Back To Top    #10

    Re: Stubborn Alkalinity

    TA of tap water is 240.

    I just retested and pH is 7.2 and TA is back to 100 so maybe I messed up the previous test.
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

  11. Back To Top    #11

    Re: Stubborn Alkalinity

    Tested again and pH is at 7.5 and TA is at 90. I dosed more muriatic acid and will test more tomorrow. Thanks to everyone for the support.
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

  12. Back To Top    #12

    Re: Stubborn Alkalinity

    Well, after adding acid again this morning my water is finally ready. I tested tonight and my pH is 7.5 and my TA is 80. I added 16.3 boxes of Mule 20 and 4.5 gallons of muratic acid. Now the waiting game to see if proportions are correct. Fingers crossed!
    Size: 21,000 w/SPA IG/Pebble & Hayward 400k BTU Heater
    Sanitizer: Hayward GLX-CELL-15-W 40K-Gallon Turbo Salt Cell + Bleach
    Filter: Hayward C5530 Cartridge Filter w/ 2-speed 2.5hp pump
    Cleaner: Black Polaris 280 w/ Booster Pump
    Install: Mar 2012, city water (no restrictions), Test kit: TF-100, Salt, Borate

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