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Thread: Lowering TA in cold water

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    Question Lowering TA in cold water

    I am lowering my TA from 160, target 90, then see how PH holds, will go lower if there is still instability.

    But I am dosing daily to keep PH at 7. This is consuming a lot of acid. The PH drifts up to 8.0 or 8.1 or 8.2? It gets high. I have been checking my levels each morning and dosing for the last 5 days. I am down to TA @ 110ppm.

    Does the temp of the water matter in keeping pH?

    The reason I am caring about my levels is I intend to use the spa from time to time. Maybe warm the pool slightly to go swimming. I see on the pool math how temp can change the CSI. What do I need to know about temp and dosing/levels?

    Am I doing things right? bring PH to 7 each day.

    Stats from today: FC 4.5, PH 8.1, TA 110, CH 190 CYA 55 water temp is 55-60. I added chlorine to bring FC to 7 and acid to bring PH to 7.
    My Pool: Guessing; 7,500g total, has a spa. WhisperFlo WFE-28 single speed, MiniMax NT 400 heater, Pentair Cart. CCP320.
    BIL pool: 16,000 total water, (650g spa). 3hp InteliFlo VS, Hayward heater (unsure of BTU), Hayward DE6000. full drain/refill on Nov. 25th, running BBB.

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    Re: Lowering TA in cold water

    When lowing the TA, a pH of around 7 allows for significantly more carbon dioxide outgassing which is the primary driver of pH rise and why aeration is such a big contributor. When aggressively trying to lower the TA, doing just what you are doing is going to yield the quickest results.

    CSI can somewhat be dismissed during this process because it is going to be unavoidably low. This more than likely won't have any ill effects because the process is relatively short in the lifespan of your plaster. Do not go much lower than 7 on the pH. Any lower and you risk damage to the copper in your heater (or anywhere else in your pool or equipment for that matter).

    Drop the pH to 7 and once it rises to about 7.4-7.5, lower it back down to 7. You get more bang for your buck with a lower pH. There is no need to wait until the pH gets to 8. Once you are happy with your TA level, let the pH settle in between the 7.6-7.8 range. Low TA with a higher pH is much more stable and will prevent the pH from creeping up too quickly.

    Using the spa with a pH in the low 7's is not an issue. Higher temperatures raise the CSI which is fine because yours will naturally be low during this time.

    Are you certain your CH is only 190? Is this a new pool? I ask because I too am in Riverside and the water out of the tap is nearly that level.

    - - - Updated - - -

    I just saw the full drain in November in your signature, disregard the last part above.
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

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    Mod Squad Jimrahbe's Avatar
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    Re: Lowering TA in cold water

    Summoner,

    I found that dosing once a day was not getting me anywhere. As Brian says, don't let the pH rise about 7.4, or so, before dosing again. I found that I had to test and dose every couple of hours.

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Calder Spa.

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    Re: Lowering TA in cold water

    Quote Originally Posted by Jimrahbe View Post
    Summoner,

    I found that dosing once a day was not getting me anywhere. As Brian says, don't let the pH rise about 7.4, or so, before dosing again. I found that I had to test and dose every couple of hours.

    Jim R.
    I haven't had the time to watch it that close. I guess I could check it after work.... but I've just been checking in the morning when I get up, dose, then check the next day.

    As of today, TA is down to 100. At nine drops I get 'red' sorta, more like pink or purple. Then I do the 10th drop and I get a solid red/magenta, but no color change with an 11th drop.

    I am figuring one or two more days of this. I've nearly used 4 gallons of acid (KemTek 10%)

    - - - Updated - - -

    Quote Originally Posted by bdavis466 View Post
    When lowing the TA, a pH of around 7 allows for significantly more carbon dioxide outgassing which is the primary driver of pH rise and why aeration is such a big contributor. When aggressively trying to lower the TA, doing just what you are doing is going to yield the quickest results.

    CSI can somewhat be dismissed during this process because it is going to be unavoidably low. This more than likely won't have any ill effects because the process is relatively short in the lifespan of your plaster. Do not go much lower than 7 on the pH. Any lower and you risk damage to the copper in your heater (or anywhere else in your pool or equipment for that matter).

    Drop the pH to 7 and once it rises to about 7.4-7.5, lower it back down to 7. You get more bang for your buck with a lower pH. There is no need to wait until the pH gets to 8. Once you are happy with your TA level, let the pH settle in between the 7.6-7.8 range. Low TA with a higher pH is much more stable and will prevent the pH from creeping up too quickly.

    Using the spa with a pH in the low 7's is not an issue. Higher temperatures raise the CSI which is fine because yours will naturally be low during this time.

    Are you certain your CH is only 190? Is this a new pool? I ask because I too am in Riverside and the water out of the tap is nearly that level.

    - - - Updated - - -

    I just saw the full drain in November in your signature, disregard the last part above.

    Yeah, full water change.

    Should I just let CH go up over time? That's what my brother in law is doing and suggesting. I agree, just wonder if it's better for the lvls to be more equal for a better CSI.

    Where in riverside? I am near box spring, maybe we're neighbors
    My Pool: Guessing; 7,500g total, has a spa. WhisperFlo WFE-28 single speed, MiniMax NT 400 heater, Pentair Cart. CCP320.
    BIL pool: 16,000 total water, (650g spa). 3hp InteliFlo VS, Hayward heater (unsure of BTU), Hayward DE6000. full drain/refill on Nov. 25th, running BBB.

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    Re: Lowering TA in cold water

    There is no need to add calcium. While the water temps and calcium levels are low, maintain a slightly higher pH and TA. Next to pH, TA has the biggest impact on CSI and it is relatively easily raise and lower. Adding calcium will be a waste of money.

    For reference, my CH level went up 400 ppm last year. Why pay for the calcium when your water department so graciously includes it?

    I'm in the Woodcrest area, so not too far...
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

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    Re: Lowering TA in cold water

    OK, specs today

    FC 6.5, PH 8, TA 90.

    Should I pull down one more time or just lower PH to 7.6?
    My Pool: Guessing; 7,500g total, has a spa. WhisperFlo WFE-28 single speed, MiniMax NT 400 heater, Pentair Cart. CCP320.
    BIL pool: 16,000 total water, (650g spa). 3hp InteliFlo VS, Hayward heater (unsure of BTU), Hayward DE6000. full drain/refill on Nov. 25th, running BBB.

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    Re: Lowering TA in cold water

    With our water temps, you are likely fine where you are now. Lower the pH to 7.6 and see how long it holds. As you continue to add acid your TA should slowly drop hopefully at the same time the water temps warm up. Use PoolMath to watch your CSI and compensate for water temp and as your CH rises.
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

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    Re: Lowering TA in cold water

    Quote Originally Posted by bdavis466 View Post
    With our water temps, you are likely fine where you are now. Lower the pH to 7.6 and see how long it holds. As you continue to add acid your TA should slowly drop hopefully at the same time the water temps warm up. Use PoolMath to watch your CSI and compensate for water temp and as your CH rises.
    Yeah I check pool math and play with the numbers daily based on the test results. I have a CSI number of -.34 @ 55*f with FC7, PH7.6, TA90, CH190, CYA 55. If I keep those number and pump the temp up to 95*f I get a CSI number of .04 I think. Looks like a pretty good range.

    I don't think I'll heat the whole pool..... just the spa from time to time for evening relaxing.
    My Pool: Guessing; 7,500g total, has a spa. WhisperFlo WFE-28 single speed, MiniMax NT 400 heater, Pentair Cart. CCP320.
    BIL pool: 16,000 total water, (650g spa). 3hp InteliFlo VS, Hayward heater (unsure of BTU), Hayward DE6000. full drain/refill on Nov. 25th, running BBB.

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    Re: Lowering TA in cold water

    Periodic spa heating sessions really aren't a significant concern with the CSI and should be dismissed.

    The CSI is nothing more than an indicator of potential issues if you maintain either very low (-0.7 or lower) or very high (+0.7 or higher) for Extended periods of time. Temporary falling into either end of the spectrum is somewhat unavoidable and will pose no risk as long as its recognized and corrected.

    Your current numbers are good for now. Keep an eye on the temp and CH and adjust accordingly.
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

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