Is a gallon of muriatic acid per week ok?

mr_gunite

Well-known member
Jun 23, 2014
66
New, England
I've been using about a gallon of muriatic acid per week to control pH and I'm just wondering if this is ok. I measure pH everyday, but I usually add the acid once per week, right after I go through my full weekly battery of tests on Saturday.

Saturday morning, I'll get done with my testing and almost consistently find the pH up around 8.2. I'll add a gallon of muriatic acid, and test again a few hours later to find it at 7.2. The reason I add once per week is because I really like to limit my exposure to the stuff and only want to deal with it once per week.

However, I'm just wondering if it seems normal for my size IGP to be using a gallon per week.

FC = 5
CC = 0
TC = 5
pH = 7.5
TA = 100
CH = 250
CYA = 40
Salt = 2000
Borate = 31.6
 

HouTex

LifeTime Supporter
Mar 7, 2011
413
Houston, Texas
If it's a new pool that's normal--at least that's about what I used for the first few months.

Now I use about a quart a week, but I have a SWG and lots of aeration.
 

epro05

Bronze Supporter
Jun 5, 2014
307
Keller, Texas
PoolMath say that for each gallon of 31.45% acid in a 23k gal pool at TA=100, TA will decrease by 22. Just wondering if you are seeing a this level of TA decrease each week? Also wondering what TA your fill water is?
 

mr_gunite

Well-known member
Jun 23, 2014
66
New, England
If it's a new pool that's normal--at least that's about what I used for the first few months.

Now I use about a quart a week, but I have a SWG and lots of aeration.

Hi HouTex. Yep, I forgot to mention this is a brand new pool finished mid-June of this year. I was thinking the rise in pH might have something to do with the new plaster, but wasn't sure.

PoolMath say that for each gallon of 31.45% acid in a 23k gal pool at TA=100, TA will decrease by 22. Just wondering if you are seeing a this level of TA decrease each week? Also wondering what TA your fill water is?

epro5: I have not tried measuring TA directly after dumping in the gallon of muriatic acid. I've only measured pH about three hours after and then remeasured TA the following week with the rest of my testing battery.
I'm going to try testing TA directly after adding muriatic acid this coming weekend though and see what drop I get. I'm also interested in the TA of my fill water. I'll try that as well.
 

ping

TFP Expert
LifeTime Supporter
Jun 24, 2011
3,144
Long Beach, CA
You should be adding the acid more often, do not let the pH rise above 7.8 as you are risking scaling when the pH is above 7.8. With time the acid demand will slow down as the plaster cures.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
11,122
Franklin, NC
You should be adding the acid more often, do not let the pH rise above 7.8 as you are risking scaling when the pH is above 7.8. With time the acid demand will slow down as the plaster cures.
:goodpost:

I was going to say that. Smaller additions several times a week are much better on the pool and equipment than huge fluctuations once a week.
 

WWells

Well-known member
Jun 3, 2013
94
Dunwoody, GA
I needed to lower PH so I bought some muriatic acid and started reading up on how to use it, I was frankly scared after reading the instructions people posted about using it, went to HD and got some PH down, don't care if it costs a couple of extra bucks

so I have 2 jugs of MA in North Atlanta (dunwoody) if anyone is interested
 

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Tepelus

LifeTime Supporter
Jun 4, 2014
121
Oslo
I needed to lower PH so I bought some muriatic acid and started reading up on how to use it, I was frankly scared after reading the instructions people posted about using it, went to HD and got some PH down, don't care if it costs a couple of extra bucks
You are better off with the muriatic acid since the PH down add sulfates in the water and in long run you might regret it. The hydrochloric acid is normally found even in human stomac so do not hesitate to use it. It is better for the pool and cheaper too.
 

peterdaly

Well-known member
Aug 14, 2013
188
Fayetteville, NY
I bet my comment is one of the ones you are referring to. I use and like 31.45 because it minimizes the volume I have to use, but yes, it's strong stuff.

I believe Home Depot near me carries a weaker one. Lowe's also has a second bottle I have never read the label of. Look for a more dilute concentration than 31.45...like 15ish.
 
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