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Thread: What is an acid demand test?

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    Join Date
    Apr 2009
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    Philadelphia PA area
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    What is an acid demand test?

    My old test kit (Pentair Rainbow Lifeguard) had an acid demand test to do if the pH was above 7.8. Since I'm constantly battling pH, I was wondering what this test is and whether it would be useful to do or not. Based on the results, it would tell me how much MA to add.
    30K IG Gunite 710 sqft - Jandy 2 HP Pump - Jandy 60 sqft DE filter
    Polaris 380 Cleaner, Pool Pilot DIG-220 SWG

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    Re: What is an acid demand test?

    Welcome to TFP!!

    I misspent many a Friday afternoon in Philly during high school, visiting bars that weren't very strict in IDing the patrons

    You've got the right idea on the acid demand test- you add drops of the reagent to the pH test you've already done until the color changes to match your desired pH, then refer to the chart to see how much acid you need to add for each 10,000 gallons of pool water. Waterbear can probably tell you how accurate the test and dosing chart are, I can't . I use mine because I have to dose hundreds of different pools - I honestly doubt that you would need it! You have the ~ same volume of water in your pool and the same demand on a regular basis. You probably know that you'll need to add "i.e. 1/4 cup muriatic acid (31.45%) every week" - if you know your pool and what it usually requires and how much a given amount of acid adds lowers the pH, why bother getting the acid demand test?

    Of course it's your choice whether to get the demand test, but I think you already know what the results would be and the proper dose of acid 8)
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  3. Back To Top    #3

    Join Date
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    Re: What is an acid demand test?

    Quote Originally Posted by tj_royersford
    ...acid demand test to do if the pH was above 7.8. Since I'm constantly battling pH...Based on the results, it would tell me how much MA to add.
    What's your TA running now?
    Lowering the TA to 70-80 if it's high will decrease the acid swings (the PH of 7.8, add MA to drop to 7.4, it rises to 7.8, add MA again).
    Triad Region of NC
    18x37 Vinyl IG (24,000 gal.), BBB & GoldLine AquaLogic PS4 SWG, Hayward 1 HP Superpump / Hayward Sand Filter / Polaris 280 cleaner / 6 deck jets / Sheer Descent Waterfall (in coping) / Brick Red Concrete Coping / Stamped Concrete Deck
    Lots of oak trees, maple trees, *and* leaves!

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    Re: What is an acid demand test?

    I like it because I am not very good at comparing reds. So if one drop of the Acid Demand Reagent drops it below my target 7.5, I wait to add acid. If it is still at or above 7.5, then I go for the MA. The color differences are just easier for me below 7.6.
    Current: 28,000G 18'x36' I/G AnthonySylvan Plaster; Waterway 60 sq.ft. DE Filter; 1.0hp x 1.65 SF Two-Speed (B2982) WhisperFlo; 2004-Present
    Previous: 40,000G 20'x40' I/G Koven unlined WWII salvage 5/8" marine steel; Lomart Stainless Sand Filter; 3/4hp Hayward SuperPump; 1946-2003 (managed by me from about 1964)
    Ancient Taylor K-2000, upgraded with Taylor CH, TA, and FAS-DPD, and TFT CYA tests.

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    Re: What is an acid demand test?

    My latest measurements from earlier today were:

    FC 14.5
    CC 0.5
    pH 7.8
    TA 100
    CH 400
    CYA 60

    I have a hard time with the reds as well. I'm partially color blind to boot so when it gets iffy I'm grabbing one of the kids to "translate" for me.
    30K IG Gunite 710 sqft - Jandy 2 HP Pump - Jandy 60 sqft DE filter
    Polaris 380 Cleaner, Pool Pilot DIG-220 SWG

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    JasonLion's Avatar
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    Re: What is an acid demand test?

    Because your CH level is fairly high, you either want to lower the TA or make absolutely sure that PH ever goes above 7.8 at any time.
    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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