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Thread: how much muriatic acid to add

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    how much muriatic acid to add

    I have a handle on everything BBB, EXCEPT, the dreaded muriatic acid. Every time I have to use it, I second guess myself. So, Here are my numbers...

    FC: 6
    pH: 7.8
    TA: 130

    THe water is clear and beautiful, but the pH is creeping up because we splash a lot and have deck jets and a slide. I am wanting to get my TA back down to about 90 to hold the pH longer. when i put in all my values, the Pool calculator says to add 104 ounces of muriatic acid. I am not positive if I was supposed to put in my pH target value as 7.2 (the number needed to drop the TA as well).

    I remember being advised to add the muriatic acid in a 'pencil stream', but I don't remember if I can put in all the 104 ounces (if that is indeed the amount) in at once or break it up over several hours.

    What do you think?
    Theresa and/or Gary

    Complete DIY: 20x40' rectangle. Resin walls, vinyl lined. 33000 gallons. Full width steps. 8' deep. Diving board, slide. Hayward pro series super pump, sand filter. Raypack 336K BTU heater. Main drain, 2 skimmers, 3 returns, 2 amerilite lights with quick change lens Aquamatic auto cover and a partridge in a pear tree.
    Breaking our backs in the hopes that one of our six kids will care for us when we are old ;)

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    Mod Squad woodyp's Avatar
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    Re: how much muriatic acid to add

    Most folks would break that up in to quart size dosages a couple hours apart. I'd do 3 doses, wait an hour then check PH to be sure you haven't overshot.
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    Mod Squad jblizzle's Avatar
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    Re: how much muriatic acid to add

    The amount of MA required for a pH change is affected by the Now TA input. The Target TA is ignored. Add the amount of acid required to lower the pH from 7.8 to 7.2 ... your numbers check out. You can do it all at once slowly in front of a return jet and make sure the pump stays on for an hour after that.

    Although, as woody said, it is often a good idea to do large changes like this in a couple steps.
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    JasonLion's Avatar
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    Re: how much muriatic acid to add

    Pool Calculator is your friend.

    It is best to make large PH changes in two steps, rather than all at once. You only need to wait half an hour, retest the PH to see if it is where you expect it to be and then adjust from there.

    Your target is to lower PH to 7.2, but aim for 7.5 in the first step.
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    Richard320's Avatar
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    Re: how much muriatic acid to add

    You did it right. You can split things up if you're worried. Compare your final results tomorrow with the expected results in the Effects Of Adding Chemicals section of the pool calculator. If you're real close, you've figured the volume out correctly and next time around you will dose with confidence.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: how much muriatic acid to add

    you all tied for 1st place as 'fastest response ever'. Thanks again for all your help. I wish this was a pyramid scheme because I have successfully converted three people to BBB.
    Theresa and/or Gary

    Complete DIY: 20x40' rectangle. Resin walls, vinyl lined. 33000 gallons. Full width steps. 8' deep. Diving board, slide. Hayward pro series super pump, sand filter. Raypack 336K BTU heater. Main drain, 2 skimmers, 3 returns, 2 amerilite lights with quick change lens Aquamatic auto cover and a partridge in a pear tree.
    Breaking our backs in the hopes that one of our six kids will care for us when we are old ;)

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