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Thread: Best way to adjust pH, TA

  1. Back To Top    #1

    Join Date
    May 2007
    Tucson, AZ

    Best way to adjust pH, TA


    I have a few questions about what & how to adjust... Here are my numbers:

    22,000 Gallon inground plaster w/ sand filter.
    FC 15
    CC 0
    pH 6.8
    TA 80
    CYA 110

    My pH has been running a little low (7.2-7.3) all summer and I haven't really been too worried about it, but it's not been this low before and I want to adjust it.

    What do I adjust first: pH or TA? I do not have a good way to aerate (return is through the in-floor cleaning system) and I'm thinking that since it's been running on the lower end of the range that I need to add something to raise it now. Should I raise the pH with Baking Soda, since that will raise my TA also? Or should I use the Borax to raise pH and then re-test and adjust TA? Also, do the borax & baking soda have to be diluted in water prior to adding or can I just dump in the powder?

    I'm using trichlor pucks as DH had no patience with bottles of bleach and his buddy told him to go buy the in-line puck feeder before I had him talked in to the Liquidator. Does the trichlor affect pH? We are in monsoon season now and getting a ton of dilution, so I'm just trying to understand if the pH is creeping down due to dilution or if there is another factor that I need to keep my eye on.

    Thanks so much for any help!!!

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Best way to adjust pH, TA

    Bring the PH up first. The TA will come up as you bring the PH up. Then make any remaining adjustment required after seeing what effect that has.

    I would start with three boxes of borax and see where that gets you. Chances are you will need more borax after that, but it is best to start will less than you think you need and see what happens. Borax and baking soda can both be poured slowly into the skimmer.

    Trichlor is acidic. Over time it will lower both PH and TA. It also raises the CYA level. Your CYA level is already getting quite high and is likely to start causing problems soon.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  3. Back To Top    #3

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Best way to adjust pH, TA

    To reeemphasize what Jason has already said, the pucks you are using are the source for your three biggest issues.......low pH, low T/A and high CYA.

    Your high CYA makes managing your FC difficult so you continue to ad more FC (Pucks) further lowering your pH, T/A and raising your CYA up to levels that will soon be very difficult to deal with.

    I would suggest you get rid of the pucks as your chlorination source but that's something the two of you will have to work out.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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  4. Back To Top    #4

    Join Date
    Jun 2008
    Tucson area, AZ

    Re: Best way to adjust pH, TA

    I'm also in the Tucson area - Marana - and my alkalinity and Ph actually tend to run a little on the high side, if anything, while using liquid bleach. And by a little, I mean really very little for the Ph, and the TA is about 120. I haven't had any Ph lock problems or any other problems with the slightly high TA. I've put some muriatic acid in when the Ph gets a little too high, but I have never had to put more than a cup at a time for my 9400 gallon pool, and that once a week or so. Tucson water does run a little high in both Ph and TA; I have tested it and also looked at the water quality reports. Your DH is making more work by having the puck feeder, not less. It takes only a few minutes to walk out to the pool and throw some liquid chlorine in it in the evenings. I and a lot of people here do it when they go out to their pool to do the evening test on the water.

    But the CYA from the stabilized chlorine is, by far, your worst problem. You can only get rid of it by draining some of the water out of your pool, and it also makes it so you have to use a lot more chlorine. Since Tucson water is not high in calcium, you can probably use cal-hypo to some extent, depending on how much calcium you already have in your pool. But even that can not be used indefinitely, because calcium hardness, like CYA, can only be removed by draining some of the water out of your pool. Trying to get DH to switch to liquid chlorine - and in Tucson you can even find it in the grocery stores - would be the best bet.

    edit: Do you even know what your CH level is? If you don't, since you have a plaster pool, and Tucson water tends to be low in calcium - check it. You might need to add some, either from calcium chloride or cal-hypo.
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    20 feet diameter, 4 feet deep
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