Pemixing, storage and use of diluted muriatic acid?

Fuldo

Well-known member
Nov 23, 2017
58
Port Orange, FL
#1
Most of my pool test readings are very stable and consistent and require little adjustment that's done over long periods. This is likely the case with most pools. I use liquid chlorine almost exclusively with pucks occasionally when the CYA drifts down and needs to be bolstered. It's an old gunite Florida pool with plaster finish and my chlorine use varies from less than 10 oz. per day in the winter to as much as 50 oz. per day in the summer on average. The chlorine use is rather predictable and it's use rather straight-forward.

The kicker is that my PH tends to drift upwards fairly quickly and needs frequent adjustment to keep PH much below 8.0. I'm using about 4 oz. of muriatic acid a day in the winter and about 8 oz. per day in the summer on average to keep the PH down to about 7.5. I've found that much less acid is required to hold PH at about 8.0 and doing so hasn't caused any problems. One of my complications is that this is a second home, I come-and-go and either a relative or my wife tends to the pool when I'm away.

Questions:
1) Should I simply allow the PH to run high, maybe 8.0 to 8.2 to minimize maintenance?
2) The others who maintain the pool aren't very comfortable with using 11% bleach. I'm wondering if it's worth prediluting some muriatic acid so perhaps one gallon or premix is needed and could be directly added per week. Is anyone else doing something like this and if so what type of containers are being used for the premix?

Any comments or thoughts would be greatly appreciated.
 

mknauss

Mod Squad
May 3, 2014
11,885
Laughlin, NV
#2
Do you have a full set of test results? I ask as depending on what your TA is it might be able to be adjusted to reduce your pH rise. Also CH to be sure calcium scaling is not an issue at higher pH.
If all good, you might consider borates to reduce your pH rise. See Borates - Why and How

You should keep the pH in the 7's. But no need to go to 7.5 if it may settle a bit higher.

You can dilute your bleach or acid. I prefer to not dilute my acid as each time you handle it there is a chance of spillage, etc. Just be sure you pour the acid into water. Not the other way around. You need to use original containers for each. Never place chemicals in containers that could be misinterpreted as for human consumption.

Take care.
 

Kiss4aFrog

LifeTime Supporter
TFP Guide
May 22, 2013
2,723
Hudson, WI
#3
I would keep the pH down in the low 7s where is should be rather than let it get up into the 8s, eye irritation, possible damage to equipment ...

You said "they" weren't comfortable with the 11% bleach, was that supposed to be acid ?? As above, if you want to dilute it, your choice. Just make sure you always add acid to water and label the bottles with the contents and strength.
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 4, 2015
3,959
CT
#4
Any pH between 7.0 - 8.0 is perfectly fine for swimmer comfort.

pH tends to rise faster from 7-7.6 or so, then the rise will tend to slow down quite noticeable. I would try letting the pH rise to a solid 8, then only push it down to 7.7 or so to see if this helps your situation.
 

Fuldo

Well-known member
Nov 23, 2017
58
Port Orange, FL
#5
Sorry everyone, I'm using 31% muriatic acid that I was thinking of diluting because other aren't comfortable with using it full strength. Then again, they're not too keen on the 11% chlorine bleach either!

Latest numbers:
FC: 7.3
PH: 7.6
TA:100
CH:280
CYA:35
Temp: 70F
Calculated CSI: 0.03

I tend to boost the FC to about 8.0 and let it drift down to about 3.0 before adding, especially in the winter, just to avoid frequent adjustments.