Lowering TA with Dry Acid Or Muriatic Acid

[CelticDaddio]

My TA is currently 230. It was recommended on another forum that I lower it according to the "HOWTO: Step-by-Step Guide to lowering your alkalinity" sticky. I read in my copy of "The Ultimate Guide to Pool Maintenance" by Terry Tamminen that you can lower TA by adding Muriatic Acid, or Dry Acid. Anyone try that?

Ed

[JohnT]

Sure adding acid lowers your TA. It also lowers your pH. When the pH goes back up, the TA goes with it, but when you aerate while the pH is low, the TA stays down.

[CarlD]

Tamminen gives the typical garbage the pool industry gives you. They love the "slug of Muriatic Acid" approach and give you a MacBeth Witches' explanation for why it works. If it does, it's incidental.

There's really only one way, short of dilution with low T/A water to lower T/A and that's what's here. It's not always clear so here's how you do it:

1) Lower pH to 7.0-7.2. (Muriatic or dry acid are both fine) This lowers T/A somewhat.

2) Aerate your water. This raises pH WITHOUT raising T/A--and it's the ONLY WAY TO DO IT!

3) Lower your pH again to 7.0-7.2, bringing T/A down some more.

4) Aerate to raise pH again without raising T/A.

5) Repeat until T/A is in the desired range.

You "ratchet" your T/A down. T/A and pH are linked. pH goes up, T/A goes up. pH goes down, T/A goes down. ONLY BY AERATION can you break that cycle and do the raising of the pH without raising T/A, allowing you to lower it more the next cycle.

The "standard" method only works if you have inadvertent aeration to raise pH that makes it look like it worked.

Worse, the "Slug" of Muriatic Acid can do major, even catastrophic damage to your pool. If that "slug" comes to rest on a vinyl liner, with its 30% concentration of HydroChloric Acid, it can dissolve your liner or weaken it enough to fail.

[CelticDaddio]

How do I aerate the pool?

Ed

Tamminen gives the typical garbage the pool industry gives you. They love the "slug of Muriatic Acid" approach and give you a MacBeth Witches' explanation for why it works. If it does, it's incidental.

There's really only one way, short of dilution with low T/A water to lower T/A and that's what's here. It's not always clear so here's how you do it:

1) Lower pH to 7.0-7.2. (Muriatic or dry acid are both fine) This lowers T/A somewhat.

2) Aerate your water. This raises pH WITHOUT raising T/A--and it's the ONLY WAY TO DO IT!

3) Lower your pH again to 7.0-7.2, bringing T/A down some more.

4) Aerate to raise pH again without raising T/A.

5) Repeat until T/A is in the desired range.

You "ratchet" your T/A down. T/A and pH are linked. pH goes up, T/A goes up. pH goes down, T/A goes down. ONLY BY AERATION can you break that cycle and do the raising of the pH without raising T/A, allowing you to lower it more the next cycle.

The "standard" method only works if you have inadvertent aeration to raise pH that makes it look like it worked.

Worse, the "Slug" of Muriatic Acid can do major, even catastrophic damage to your pool. If that "slug" comes to rest on a vinyl liner, with its 30% concentration of HydroChloric Acid, it can dissolve your liner or weaken it enough to fail.

[JohnT]

How do I aerate the pool?

Ed

A fountain, point the returns at the surface, or get a bunch of kids in there to splash around.

[CelticDaddio]

You mean just a plain ol' fountain like this:



And point the skimmer returns up to the surface?

Ed

A fountain, point the returns at the surface, or get a bunch of kids in there to splash around.

[CarlD]

That's all you need!

[CelticDaddio]

So my procedure to lower my TA is

1) Lower pH to 7.0-7.2. (Muriatic or dry acid are both fine) This lowers T/A somewhat.
2) Turn on the fountain
3) Lower pH again to 7.0-7.2, bringing T/A down some more.
4) Turn on the fountain again
5) Repeat 1-4 until T/A is in the desired range.

Is there a formula for how much Muriatic acid, or dry acid to add to reduce the ph? I.e. 1/4 cups of muriatic reduces pH by 0.5, or is it not that simple?

That's all you need!

[CarlD]

So my procedure to lower my TA is

1) Lower pH to 7.0-7.2. (Muriatic or dry acid are both fine) This lowers T/A somewhat.
2) Turn on the fountain
3) Lower pH again to 7.0-7.2, bringing T/A down some more.
4) Turn on the fountain again
5) Repeat 1-4 until T/A is in the desired range.

Yup that's it.

[Watermom]

In a 33,000 gallon pool, it is going to take about 26 oz. of muriatic acid to lower the ph by approximately 0.2. Don't try and get to your target in one dose. Small doses (maybe a pint at a time) added in front of a return jet slowly. Be careful not to splash any on you or on your liner. Also, don't breathe the fumes. Wait several hours to let it circulate, then retest and redose as needed.