Muriatic Acid Demand

George Whitzel

Well-known member
Jul 23, 2017
199
San jose, california
Current readings are:
FC 6
CC 0
PH 7.6
CYA 70
CH 300
TA around 100

I am having to use 1.5 to 2.0 gallons of MA a week to keep my PH at 7.4 to 7.6. I wait unti it get to 8.0 before added the acid to lower the PH. I usually check the PH every 3 days. The acid I am using is from Home Depot and is 14.5%. Is this normal? Does my SWG have an impact on PH?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,073
Laughlin, NV
What is your fill water TA? I suspect it is pretty high. As you are using half strength acid, you use more.

Your SWCG has no appreciable effect on your pH.
 

George Whitzel

Well-known member
Jul 23, 2017
199
San jose, california
My fill water TA is around 80. There is no Loew's in my town only a Home Depot. I guess what everyone is saying is that since I am using a lower baum acid it is not unusual to be using the amount weekly that I am using. Is that correct?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,073
Laughlin, NV
If your pH is reacting and your TA, as you state, is around 100, then the acid amount you are using is needed. It is the amount needed to keep your TA at the 'around 100' while adding your 80 TA fill water due to evaporation.

If the acid added was excessive, your TA would be going much lower over time.
 

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
1,606
Rancho Cucamonga, CA
In So Cal (and probably all of CA), Lowe's and HD only sell 14.5% MA. You may be able find a pool store in your area that carries HASA refillable containers of 31.45% for about the same price as the lower strength MA.

Your MA usage is inline with mine. Aeration caused by spa spillovers or water features will increase the rate of pH rise.
 

Jeff J.

Well-known member
Aug 6, 2019
222
Staten Island NY
If your pH is reacting and your TA, as you state, is around 100, then the acid amount you are using is needed. It is the amount needed to keep your TA at the 'around 100' while adding your 80 TA fill water due to evaporation.

If the acid added was excessive, your TA would be going much lower over time.
I thought I've heard numerous times that an SWG does tend to raise PH. That's not true?
 

George Whitzel

Well-known member
Jul 23, 2017
199
San jose, california
That is what I heard also so that is why I asked the question?

Also just verified tha both Loew`s and HD in my area only sell the 14.5% MA. ACE hardware does sell the higher baum (31.4%) acid but only in one gallon jugs. I think it cost around $16/gallon but since it is double baum of the other stores it is probably worth it.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,073
Laughlin, NV
I thought I've heard numerous times that an SWG does tend to raise PH. That's not true?
It adds a small amount of aeration. In general, it is not an appreciable amount. Many members in areas that they do not add high TA fill water (or any at all due to rain) and have no aeration from water features have a very stable pH with a SWCG.