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Thread: Newbie question about Acid demand

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    Newbie question about Acid demand

    Basically, I have a SWG. My water test on 5/26 was

    FC: 2
    TC: 2
    CYA: 60
    PH: 8.2

    I added 2 Quart of 14.5% acid (kem-tek hydrogen chloride) into the pool. I turned off SWG and solar panel. Added 1/2 qtz at a time (mixed with a bucket of water). Ran the pump for 5 hours, and next day I check PH only drop to 7.8. My target was 7.2.

    Does it take so much acid to lower the PH? even though I poured in 2 quart of 14.5% acid, it only lowered it by .4 ph .

    Do I need to add acid every week for a SWG system?

    regards,
    Laurence...
    14.5K gal, spa, plaster,waterfall, 1.5hp pump, chlorine tablet

  2. Back To Top    #2
    JasonLion's Avatar
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    The amount of acid you need depends on your TA level, borate level, how recently the pebblesheen was applied, and other factors. By adjusting some of those things you can minimize how much acid you need to use.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3
    Hi,
    My TA level is 80. Pool was completed sometime on April 10. So it's still quite new. I don't think I have any borate in the pool. So it's possible that my pool still need to stabilize due to it being new?

    I also seem to have to set my SWG to 85% to maintain it at 2% FC. SWG started in 5/1 when it's still very cold at 45% production. I run my pump for 5 hours a day, not sure if that is sufficient. Pool builder told me to run it 12-6pm and I recently set it to run 1pm - 5pm. I did a test before to check if I have algae by generating FC at 3ppm at sunset and check it again in the morning and it's about the same ppm. So I assume that's ok. I guess I am trying to balance required maintenance vs electricty usage too.

    Thanks in advance.

    regards,
    Laurence...


    Quote Originally Posted by JasonLion
    The amount of acid you need depends on your TA level, borate level, how recently the pebblesheen was applied, and other factors. By adjusting some of those things you can minimize how much acid you need to use.
    14.5K gal, spa, plaster,waterfall, 1.5hp pump, chlorine tablet

  4. Back To Top    #4
    JasonLion's Avatar
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    For the first three weeks after the pebblesheen is applied the PH will rise rapidly, and it will continue to rise more slowly for up to a year. It is important that you keep the PH below 8.0. If the pH gets too high you can have calcium scaling, which can be very difficult to clean up.

    Experiment with the quantity of acid, increasing the amount you use gradually, till you find the amount of acid you need to get the PH down to around 7.2. While experimenting you should test the PH about an hour after adding acid so you don't get fooled by the increase overnight.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  5. Back To Top    #5
    I manage to get my PH down, but now it's PH 7.1 instead of my target of 7.2. Is 7.1 safe for swimming?

    Tomorrow the SWG will start again, and wondering if that will increase the PH level. I'll check again before jumping in.

    My last check is

    TA: 80
    PH: 7.1
    FC: 1.5 (i added some chlorox to get this since my SWG is off the whole day)


    I guess I am getting a little bit more comfortable with adding acid now and being careful with the amount added. I assume now I should just maintain it by adding it little by little once a week to keep it below 7.8? Is that a good assumption?

    Thanks in advance.


    regards,
    Laurence...
    14.5K gal, spa, plaster,waterfall, 1.5hp pump, chlorine tablet

  6. Back To Top    #6
    JasonLion's Avatar
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    The PH will be going up, both from the fresh plaster in the pebblesheen and from the SWG.

    PH at 7.1 can cause some eye irritation. By tomorrow the PH will be higher.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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