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Thread: Ph and TA after replastering

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    Ph and TA after replastering

    Our pool was re-plastered in early March. The company that did the re-plaster took care of the start up. This included the 2 weeks of daily brushing and balancing of chemicals. After returning pool care over to me, I have continued to brush at least once a week, more like once every 5 days. I monitor the pH daily daily and make adjustments to keep at 7.5. I have a few questions on water chemistry and what to expect over the next 6-12 months. I'll first show recent test results using the TF-100 kit:

    FC= 3
    pH=7.8 (before adding acid today)
    CyA=35
    TA = 70
    CH=230

    I am adding 2 cups of muratic acid daily to keep at 7.5. I have checked several hours after adding to see if pH has dropped and it does. Next morning it will be 7.8 again. Is this a typical daily pH increase for newly plastered pools.

    I have been trying to get TA up to around 100 ppm. I'll add the pool calculator estimate of baking soda. The TA will come up but then work back down over time. The highest I've had it is 90ppm. Does the daily addition of acid cause the TA to go back down? Am I working the two against each other? Before the the replaster job, the TA stayed around 60 ppm. I never tried to increase because my pH was steady.

    Pump run time - during the break-in phase the pump ran 24/7. Now that I am couple months out, is it okay to let the pump switch off at night. I've read other places that the pump should run 24/7 the first year but I have not seen that same info here. Pool builder did not say specifically but because he preaches about the poor efficiency of sand filters, he will tell me to run 24/7 just for filtering purposes.

    BBB method question - now that it is getting very warm and the chlorine demand will increase, what is best method for adding bleach. Boost the chlorine once in the morning to provide needed amount for day or break the dosage up and add 2-3 times. This is my first full summer with a pool so I'm not sure how much bleach will be needed daily. I didn't start the BBB method until late September of last year. So haven't had the full heat of summer experience.

    Thanks
    20K IG gunite
    TR-60 Sand Filter, 1HP Pentair single speed pump
    Memphis TN

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    Mod Squad jblizzle's Avatar
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    Re: Ph and TA after replastering

    1. Could be normal. The rise should slow down as more time passes
    2. Every time you add acid, that lowers the pH and the TA ... that is why you TA keeps dropping. Just keep adding baking soda as needed (although no need to try to get it up to 100)
    3. If you do not see any plaster dust when you brush, you should not need to be running nearly that long. Likely 6 hours is more than enough at this point. Usually only need to run 24/7 for a week or two.
    4. Usually best to add your bleach in the evening (although really does not matter). Only once a day should be fine. Just make sure you add enough so that it never drops below the minimum for you CYA level by the next time you test and dose. The pump needs to be on at least 30 minutes before you test and after you add chemicals, so that may dictate your schedule somewhat.
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    Richard320's Avatar
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    Re: Ph and TA after replastering

    Quote Originally Posted by curlytop09 View Post
    Our pool was re-plastered in early March. The company that did the re-plaster took care of the start up. This included the 2 weeks of daily brushing and balancing of chemicals. After returning pool care over to me, I have continued to brush at least once a week, more like once every 5 days. I monitor the pH daily daily and make adjustments to keep at 7.5. I have a few questions on water chemistry and what to expect over the next 6-12 months. I'll first show recent test results using the TF-100 kit:

    FC= 3
    pH=7.8 (before adding acid today)
    CyA=35
    TA = 70
    CH=230

    I am adding 2 cups of muratic acid daily to keep at 7.5. I have checked several hours after adding to see if pH has dropped and it does. Next morning it will be 7.8 again. Is this a typical daily pH increase for newly plastered pools. Yes.

    I have been trying to get TA up to around 100 ppm. I'll add the pool calculator estimate of baking soda. The TA will come up but then work back down over time. The highest I've had it is 90ppm. Does the daily addition of acid cause the TA to go back down? Am I working the two against each other? Before the the replaster job, the TA stayed around 60 ppm. I never tried to increase because my pH was steady. Yes, you're working against yourself. TA will rise as the plaster cures.

    Pump run time - during the break-in phase the pump ran 24/7. Now that I am couple months out, is it okay to let the pump switch off at night. I've read other places that the pump should run 24/7 the first year but I have not seen that same info here. Pool builder did not say specifically but because he preaches about the poor efficiency of sand filters, he will tell me to run 24/7 just for filtering purposes. If you're past the cloudiness after brushing the fresh plaster, you can reduce the run time. There's an article in Pool School.

    BBB method question - now that it is getting very warm and the chlorine demand will increase, what is best method for adding bleach. Boost the chlorine once in the morning to provide needed amount for day or break the dosage up and add 2-3 times. This is my first full summer with a pool so I'm not sure how much bleach will be needed daily. I didn't start the BBB method until late September of last year. So haven't had the full heat of summer experience. Pour liquid bleach in front of the return. It doesn't matter when, as long as it never dips below the minimum for your CYA level and the pump runs at least another half an hour to circulate it. How much depends entirely on what the test results say and what poolmath calculates. Ballpark figure for your pool, maybe half a jug of 8.25% Chlorox. Stronger chlorine will mean less, but it's all dependent upon test results.

    Thanks
    Have you read the article on new plaster startup?
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: Ph and TA after replastering

    Yes I did read the article and had printed out for reference before pool re-plaster started. Good info and helped when working with builder over the 2 week period break in. I just needed some verification on the after break-in. I stopped running the pump 24/7 after 3 weeks but had read that this was not good idea. From responses above, I'm doing everything right (except for the TA maybe). I may be running pump a longer than needed, about 10 hours right now.

    The pool calculator is a great tool and I know how much 8.25% bleach I need for each ppm rise in Cl I want. Just needed to know best approach for adding and keeping levels above minimum as I learn what to expect for usage over the summer.

    Thanks for help above.
    20K IG gunite
    TR-60 Sand Filter, 1HP Pentair single speed pump
    Memphis TN

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