Seem to be using more MA this season to keep pH and TA down

[QingGuy]

FC 5
CC .5
pH 8 (typically keep this at 7.6)
TA 80
CH 400
CYA 60
CSI .43

I'm currently going through about 50oz of MA a week. I don't recall past usage being this high. My TA keeps creeping up, too. My pool is 10 years old, and I did have it acid-washed this past spring. Could this be what is causing the pH and TA to rise so quickly? I have water features but rarely run them.

 

[JohnT]

Hard to say. 50oz a week is not a lot.I could put a gallon a day in mine and never have low pH.

How often do you add water, and what is the TA and pH of your fill water?

 

[QingGuy]

Hard to say. 50oz a week is not a lot.I could put a gallon a day in mine and never have low pH.

How often do you add water, and what is the TA and pH of your fill water?

Good questions. Water is on autofill, so I have no idea how often it is added. Local water: pH 7.8 and CH 280-300

 

[mknauss]

TA is 130 ppm of fill water.

More evaporation this summer. Thus more TA added, and thus more acid needed. Mine is up quite a bit too.

 

[proavia]

Your high evaporation rate and high CH /high TA fill water is causing your CH and TA to rise.
Higher TA causes the pH to rise a bit quicker.
Having an acid wash done (which reduced the life of your plaster based pool surface) may also lead to an increase in acid demand for a while as well as it exposed virgin plaster.

Chances are, the entire volume of your pool (or more) evaporates every year.
Work your TA down to 60.
Keep CSI between 0.00and -0.30 (negative 0.30) to minimize calcium scaling.
Consider adding a water softener and plumbing it to your autofill to help keep CH rise to a minimum (no effect on TA) and add a SWG for chlorine additions.

 

[mknauss]

Chances are, the entire volume of your pool (or more) evaporates every year.

It is closer to 1.5 times the pool volume each year ---

Mine is over 2 times pool volume a year, but we are hotter here in Laughlin vs Vegas.

 

[proavia]

It is closer to 1.5 times the pool volume each year ---

Mine is over 2 times pool volume a year, but we are hotter here in Laughlin vs Vegas.

Wow - the lower humidity probably doesn't help either.
In PHX, I'm about 1 to 1.5 the volume per year.

 

[QingGuy]

TA is 130 ppm of fill water.

More evaporation this summer. Thus more TA added, and thus more acid needed. Mine is up quite a bit too.

Thank you. I hadn't even thought of that.

 

[QingGuy]

Your high evaporation rate and high CH /high TA fill water is causing your CH and TA to rise.
Higher TA causes the pH to rise a bit quicker.
Having an acid wash done (which reduced the life of your plaster based pool surface) may also lead to an increase in acid demand for a while as well as it exposed virgin plaster.

Chances are, the entire volume of your pool (or more) evaporates every year.
Work your TA down to 60.
Keep CSI between 0.00and -0.30 (negative 0.30) to minimize calcium scaling.
Consider adding a water softener and plumbing it to your autofill to help keep CH rise to a minimum (no effect on TA) and add a SWG for chlorine additions.

Thank you. I hadn't even thought about the TA level going into my pool.