# Thread: muiatic acid

1. ## muiatic acid

I went into pool math to figure out how much acid to add to lower TA, but I am not sure how this works. According to the pool gallons of water I have about 11,700 gallons of water. My TA is 170. I clicked on the calculation for 5 ounces and it says it will bring it down .8? Is that what I am looking to do?

2. ## Re: muiatic acid

What are you trying to get your TA down to? In Pool Math, the Now column is for what you just tested and the Goal column is what you should try to be at. At the very bottom, you will need to fill in the info under Suggested Levels. That helps with establishing your goal column.

3. ## Re: muiatic acid

When lowering TA, the calculator won't tell you how much acid to add for the TA specifically. You need to focus on the pH row and lower that to about 7.0. For example, if your pH is currently 7.8, use enough acid to lower it to 7.0. By doing that, the TA will come down a bit. Then aerate to raise the pH so you can do it all over again, and again, or as much as needed until you get the TA you want. Does that help?

4. ## Re: muiatic acid

That's not exactly how it works. Check out this link. Pool School - Lower Total Alkalinity

Basically you lower your pH to the lowest "safe" number, aerate the water to raise pH again (or just wait for it to rise on its own) and then lower pH again. Repeat.

5. ## Re: muiatic acid

Yup. what ^^^ they said.

Dropping TA is a byproduct of lowering the PH. Over a period of time, the TA should come down on its own as you maintain the pH. But if you want it to happen faster, then lower pH to 7, aerate to bring it back up, and then repeat.

6. ## Re: muiatic acid

Is PH 7.0 OK for a salt pool? In pool school it said 7.6-7.8, but because the TA is so high I am guessing I need to lower the ph first to 7.0 to bring down the TA? I guess I will just add a little muriatic acid at a time and keep testing. How long does it take the acid to bring down the PH? In other words when should I test the water after adding the acid?

- - - Updated - - -

That link helps a lot! Thank you Mr. Bruce! I think I got it now, lower PH to 7.0 with acid, then aerate to raise the PH which won't raise the TA, repeat as needed. I also see wait 30 minutes before testing so that answers my question. I can do this!

7. ## Re: muiatic acid

I have a 11,100 gallon salt water pool and go buy a single quart of MA at ace hardware (I don't like to store any at my house) then add the full quart (slowly over a return then brush the area). If my PH is 7.8ish when I add the quart then it drops down to 7.2. I test 1 hour after I add the acid. Make sure your pump is running the entire time.

I used to have to add it weekly, but now that my TA is down to 75 I can go a few weeks without having to add any MA.

8. ## Re: muiatic acid

i always add, make sure not to put any commas in the pool volume field in the calculator.

9. ## Re: muiatic acid

Any pH in the 7's is acceptable but a narrower "more preferred" range is 7.4 - 7.8. No real drawback unless you get outside the 7's

10. ## Re: muiatic acid

On the Pool Math page at the bottom is a section entitled "The Effects of Adding Chemicals". If you enter in the amount of acid you plan on adding, it will tell you how much the TA is lowered by. This is an exact number (unlike the pH change which involves some assumptions) because the chemical reaction between adding acid and alkalinity in the pool water is well defined. So if that section tells you that adding XX oz of acid will reduce your TA by YY ppm's, it will be pretty close. The only time it's a little bit off is if you have borates present in your water as that affects the amount of acid required to lower pH and that section of Pool Math assumes that borates are zero unlike the section above which uses borates to calculate pH changes.

11. ## Re: muiatic acid

Ok so I added the first amount, used the pool brush to mix up the water, I see now my salt nano cell is saying "warning" add 90 pounds of salt. Should I shut the cell off and leave the filter running until I get the PH and the TA down?

12. ## Re: muiatic acid

Ended up cleaning the blades on the cell according to the manufacturer's manual-1 part ma and 4 parts water let them soak 15 minutes and rinsed it. Put it all back together and turned everything back on, not asking for salt anymore. whew. Checked the PH it's at 7.2 so I added a teeny bit more MA and stirred. Also thank you serious1 -had no idea about TA being too high and causing issues and needed to be regulated weekly, that is good to know, although I definitely added less than a quart to bring the PH down to 7.2 but I guess all pools are different depending on location, environment, use, etc.

13. ## Re: muiatic acid

good to hear that it worked out! My TA was 230 when I started so PH was raising daily (I don't have any aeration, just the swg). Now that TA is under control PH seems to be behaving. CYA probably helped me too, I didn't have any when I started the process of lowering TA and got that up to 65. I test PH & FC daily. I only test TA after I dose with MA to see if it's still ok. My city fill water has high TA.

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