My pool is a year and a half old, and I need to add a ton of acid. It is 9k gallons, and add 25 oz a week. After a week, it is dark purple on the Taylor test kit (8+). I just tested my TA and it is so low, it does not register. What do I need to do to get my ph to stabilize?
Small pool goes through acid
- Thread starter Wire4money
- Start date
Start by giving us some additional details on all of your current levels from your Taylor test kit.
PH
FC
CC
TA
CH
CYA
Are you chlorinating your pool with liquid chlorine or a SWG?
PH will naturally rise in your pool on its own. In addtion any water features contributing to aeration such as the jets from a spa, air blowers for a spa, splashing and swim load of swimmers ect will contribute to the rise of PH. Also I see your pool is not brand new but even the continuing curing of plaster can drive it up sligtly although probably not a big contributor at this point.
One of the contributing reasons your PH is not stable is due to your alkalinity levels. Each time you add acid your alkalinity levels will decrease slightly. You will need to add sodium bicarbonate or baking soda to compensate any drop in your alkalinity levels and keep them where they need to be.
Once we get a total picture of your current levels we can give some guidance on the best way to proceed.
PH
FC
CC
TA
CH
CYA
Are you chlorinating your pool with liquid chlorine or a SWG?
PH will naturally rise in your pool on its own. In addtion any water features contributing to aeration such as the jets from a spa, air blowers for a spa, splashing and swim load of swimmers ect will contribute to the rise of PH. Also I see your pool is not brand new but even the continuing curing of plaster can drive it up sligtly although probably not a big contributor at this point.
One of the contributing reasons your PH is not stable is due to your alkalinity levels. Each time you add acid your alkalinity levels will decrease slightly. You will need to add sodium bicarbonate or baking soda to compensate any drop in your alkalinity levels and keep them where they need to be.
Once we get a total picture of your current levels we can give some guidance on the best way to proceed.
Last edited:
- Jul 21, 2013
- 65,680
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Your last PoolMath log was in 2021.
Post a complete set of test results.
What test kit are you using?
How do you chlorinate your pool?
Your pool have any water features?
What strength Muriatic Acid are you using?
25 oz of 31% MA will lower a 9000 gallon pool pH by 0.7 and TA by 11.
Are you adding 25oz of MA in one dose?
Post a complete set of test results.
What test kit are you using?
How do you chlorinate your pool?
Your pool have any water features?
What strength Muriatic Acid are you using?
25 oz of 31% MA will lower a 9000 gallon pool pH by 0.7 and TA by 11.
Are you adding 25oz of MA in one dose?
I’ll do a full test tomorrow. I have a salt water generator, but had to drain the pool in the fall for a repair. When I filled it back up in November, I used tabs through the winter to chlorinate and add cya. Being winter, we weren’t using it, have no attached spa, and have not ran our waterfall. Our fill water is very hard, with a ta of 120ish.
- Jul 21, 2013
- 65,680
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
TA of 120 is at least part of your problem.
Were you needing to lower the pH using MA in the winter while using the tabs?
Were you needing to lower the pH using MA in the winter while using the tabs?
- Jul 21, 2013
- 65,680
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
PH should not be rising with 0 TA. Something does not pass a reasonability test. Give us a full set of numbers.
You should not lower your pH by more then 0.4 at one time. I would do three 8oz of MA every 2 to 3 days rather then one 25oz dose once a week.
Let's have @mknauss who is in your area look at this.
This is not possible.
At 0 TA the pH would be 4.5 or lower.
One or both tests are incorrect.
Before I added 25oz of acid and approx 8 lbs of baking soda, it was 8+ ph and no ta. It is now sitting at 7.2 ph and 80 ta. Chlorine is at 3, and ch at 375ish.
- Jul 21, 2013
- 65,680
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- Jul 21, 2013
- 65,680
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
What is the CYA?
If the TA is now 80 ppm, it would have had to start at 28 ppm before adding the acid and baking soda.
28 + 63 - 11 = 80.
If the TA is now 80 ppm, it would have had to start at 28 ppm before adding the acid and baking soda.
28 + 63 - 11 = 80.
Taylor test kit that is recommended here. I have a hard time with cya, I’ll test that tomorrow.
80 was when the color completely changed. Before, the color was already red before adding drops. Also, technically the pool is somewhere around 8700.
an1vrsy
Bronze Supporter
- Jul 10, 2018
- 1,240
- Pool Size
- 26000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Hey neighbor, for perspective, I have a 26k gallon pool filled March of ‘21 and I have to add MA every 4 to 5 days. We have extremely high TA fill water here in Las Vegas. Only in the summer, do I make an effort to lower TA to slow down pH rise.
That’s where I’m confused. I’ve measured our TA at 110 last year. Being winter, water isn’t evaporating as quick, but with adding MA, the TA keeps dropping. Everything says with low TA, I should not have high PH.
an1vrsy
Bronze Supporter
- Jul 10, 2018
- 1,240
- Pool Size
- 26000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I measured TA just yesterday or so, it was 140 ppm. pH was 7.7. As others have posted, it is hard to have TA 0 without crashing your pH. You just posted you tested TA last year, that’s over 90 days ago. Run a full set of test results with your Taylor K2006 and post your results.
- Jul 21, 2013
- 65,680
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
You now have pH of 7.2 and TA of 80. Let’s move forward from here.
Log every test and every chemical addition in PoolMath and we can all track what is happening.
Also log any fill water added to the pool.
Do you have an autofill?
Test your pH every 2-3 days and your TA every time before you add MA.
Confirm you are no longer using tabs.
Log everything and point out here when you think something is questionable.
Log every test and every chemical addition in PoolMath and we can all track what is happening.
Also log any fill water added to the pool.
Do you have an autofill?
Test your pH every 2-3 days and your TA every time before you add MA.
Confirm you are no longer using tabs.
Log everything and point out here when you think something is questionable.
The pH can't be high if the TA is zero, so something is off.
The CYA might be super high and that can cause problems.
Super high chlorine can affect the pH reading.
CYA can’t be high. Pool was drained for repair November. Chlorine demand was low all winter, so minimal tabs were used. I plan on testing CYA and if it’s 50ish, turning on the salt generator.