Muriatic Acid Concentration

Rick T

Well-known member
Apr 28, 2019
109
Houston, TX
Hi. I just upgraded to a premium on the app. As I use the pool math app it gives me the option of 14.5% and 29% for muriatic acid. I get this stuff from Home Depot. Should I just use the 29% figures?


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Rick T

Well-known member
Apr 28, 2019
109
Houston, TX
Also, as I get my ph (which is currently 7.8) back down to 7.0-7.2, how soon will my TA respond and go down? How soon do I retest TA? You helped me with a month ago with issues. I eventually had to empty my pool and start over. My replaster guy came out yesterday and polished the pool, I had white spots and he over acid-ed my pool making it rough and gritty. (thus another empty and refill). I'm trying to get the newly added water to the right numbers.
 

setsailsoon

Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
3,508
Stuart/FL
Baume is a measure of viscosity. Some manufacturers control the process to a given viscosity that yields 31.45% MA. It's always seemed weird to me that they market to the public using Baume which is a term that very few people understand or even care about.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,378
Tucson, AZ
Baume is a measure of viscosity. Some manufacturers control the process to a given viscosity that yields 31.45% MA. It's always seemed weird to me that they market to the public using Baume which is a term that very few people understand or even care about.
It a measure of specific density, not viscosity. When dealing with highly concentrated solutions, especially ones that are as acidic as MA, it’s far easier to use density as a process control rather than trying to measure concentration. You can’t use a pH probe to measure concentrated acidic or caustic solutions, but you can easily use a mechanical float as a visual indicator. Baume was also used in pharmaceutical applications as it was originally used to compare the salinity of various solutions.
 
Last edited:

setsailsoon

Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
3,508
Stuart/FL
It a measure of specific density, not viscosity. When dealing with highly concentrated solutions, especially ones that are as acidic as MA, it’s far easier to use density as a process control rather than trying to measure concentration. You can’t use a pH probe to measure concentrated acidic or caustic solutions to measure concentration, but you can easily use a mechanical float as a visual indicator. Baume was also used in pharmaceutical applications as it was originally used to compare the salinity of various solutions.
Yep, gravity not viscosity. Thanks.
 

Rick T

Well-known member
Apr 28, 2019
109
Houston, TX
Yesterday I added 7 pounds of Calcium Hardness Increaser from Home Depot. My CH was 225. We got about an inch of rain overnight, I tested the water this morning at my CH is lower, 175. I took my sample about 12" deep and the pumps had been on for about an hour. My ph is still low at 7.2 (up from 7.0 yesterday). I retested TA and it has fallen from 210 to 180. I plan on keeping ph between 7.0 and 7.2 until TA gets to the acceptable range of 79-90. How long should it take to drop? Thanks.
 

Rick T

Well-known member
Apr 28, 2019
109
Houston, TX
Also, I need a better tutorial for the Pool Math app. I upgraded to premium yesterday. Since I'm starting with a new complete water fill I started a new log. I inputted today's readings but it still shows yesterday's values. I added the reminder to clean the filters but the reminder came up immediately and I don't know how to reset it.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,378
Tucson, AZ
When you add muriatic acid to pool water it instantly reacts with bicarbonate and converts it to dissolved CO2. The pH drops along with the TA. As the CO2 outgasses from the water, the pH rises. So you have to wait for the pH to recover a bit and then add more acid. I would suggest you wait until the pH gets to 7.6 and then you knock it down to 7.0 again. Aerating the water by running water features or spa jets can help to increase the rate of pH rise. Reducing TA is a process, not a one time treatment.

Lower Total Alkalinity - Trouble Free Pool
 

Rick T

Well-known member
Apr 28, 2019
109
Houston, TX
Thanks. I have the waterfall on. ph is up .2 from yesterday and TA down 30. Will do as you said, wait for 7.6 then hit it with the recommended muriatic acid to get back down to 7.0.
 

Rick T

Well-known member
Apr 28, 2019
109
Houston, TX
Also, I need a better tutorial for the Pool Math app. I upgraded to premium yesterday. Since I'm starting with a new complete water fill I started a new log. I inputted today's readings but it still shows yesterday's values. I added the reminder to clean the filters but the reminder came up immediately and I don't know how to reset it.
I found the video on YouTube that helped. Thanks.