Pump Off When Raising And Lowering TA (Total Alkalinity)

by TOM

Remember: The pump motor MUST be off when increasing or decreasing your pool total alkalinity.

WHY (pump off)?

Give reasons for it, please!

Thanks for your question Tom

This is an area of debate so I'll try to be as concise as I can.

The swimming pool pH level and total alkalinity are opposite sides of the same coin. What you do to one side may, to a lesser effect, contribute to the other side. Every pool guy that I've ever talked to will say this is correct.

The debate is HOW to raise the pool alkalinity without much happening to the pH level, or vice versa. This is my take on the subject. There is a process called aeration that many pool owners use and many pool experts tell their customers. This basically means that when you have a high pH level (and the definition of high is debatable as well) and high alkalinity, you need to pour the muriatic acid in the pool and introduce movement and air into the pool.

This is accomplished by turning on the pump motor, having any water features such as slides, water falls, or even renting an air pump and placing the hose into the pool to introduce air in the pool water. "The acid/aeration process to lower TA:

1. Add acid to lower your PH to between 7.0 and 7.2 (this also lowers TA)

2. Aerate until pH level rises to around 7.6 (the only way to raise PH without also raising TA)

3. Repeat steps 1 and 2 until you reach the desired TA."

I have also found this post on another pool site to lower the pH and pool alkalinity.

"Aeration can be provided by a SWG, spa jets, waterfall, fountain, return pointed up so it breaks the surface, air compressor, kids splashing, rain, etc. This post, this one, and this one show examples of home made fountains and this post shows a spa style jet that fits into a return."

Some of these are true, but a closer look says that right after you add muriatic acid, which is one of the most caustic acids on the market, to have your kids jump in the pool to raise the pH level. Sorry, but I think this is totally irresponsible. If the child swims through a hot spot of acid with his eyes open, he's going to have a problem.

What is happening is the CO2 is being burned off, raising the pH level, while leaving the total alkalinity alone. I have made it very clear throughout this site that I'm the pool operator at our local YMCA. It's an 80,000 gallon pool with about 4,000 - 5,000 swimmers per month. I started in pools back in 1999 and learned from my uncle who owned a very large and successful pool business in Arizona.

Now, the Y pool is open from 5am - 9pm Monday - Friday, closed at 5pm on Saturday and 4pm on Sunday. All of these times the pool is open. The exception is Tuesday and Thursday when the pool is closed from 8am - 10:30am. This is the window that I have to make all of my adjustments.

I don't have time to rent an air compressor and we don't have slides or water features when I need to raise or lower anything. I also deal with the Oregon Health Board who can come in at any time to test the pool water so I ALWAYS need to be on the mark...every time...no exceptions. If I'm not I'll have several hundred people angry with me because the swimming pool is closed, not to mention having answers for my supervisor.

Now back to your question...

The above way to lower your pool's total alkalinity may work, but, and this is the big but, I have found through personal experience, it takes longer and cost more in pool chemicals. Why lower the swimming pool pH level when you just need to lower the total alkalinity? Time is not my friend and lots of money is not what the YMCA has.

When you do the above you're lowering both the pH level and alkalinity. When the swimming pool pH level is within range, between 7.6ppm - 7.8pmm, you can raise or lower the pool alkalinity without much happening to the pH level using this method:

Pool Alkalinity In Swimming Pools

Swimming Pool pH Levels

When we have fill water of 8.0 and total alkalinity of 30ppm, (total opposites), I need to know the most timely, efficient, and cost effective way to make adjustments to a heavily used commercial pool. I've done that for over 2 years.

I can raise the pool alkalinity from 80ppm to 100ppm using 400oz. of Sodium Bicarbonate while keeping the pool pH level at a very consistent 7.6 - 7.8ppm. This is accomplished even with fill water pH being 8.0 and alkalinity 30ppm.

In the last 2 years I have saved the YMCA nearly $15,000 in chemical usage, as opposed to the previous years that I was not there. Their budget was around $800 per month for chemicals; I now have it down to around $120. That is over $8000 a year in chemical savings.

I can say with much confidence that I have mastered the basics in how to raise and lower, to increase and decrease a pool's chlorine, pH level, alkalinity, cyanuric acid, and calcium hardness. I always ask myself, "Who do I listen to, and why? Does this person have the experience and, most importantly, the proof and evidence, that what he says works?"

"Do I listen to the chemical companies and pool stores telling me to shock the pool every week, even though my swimming pool is crystal clear, all the readings are perfect, and the combined chlorine level is 0.0ppm?" "Why would they want me to shock every week? Is it to have a cleaner and safer pool, or do they just want to sell more products?"

This site is not meant to give the molecular structure of swimming pool chlorine, or the exact chemical make-up calcium chloride. It's to give the average pool owner a good foundation and information that they can use to have the best swimming pool possible with the least amount of effort and pool chemicals.

This is what average pool owners want, and this site gives it to them. Have a great day and I hope this answers your question


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Oct 05, 2017
High pH levels and Low alkalinity levels
by: louise

Hi I am having trouble with my pH levels being stuck at 7.8ppm which I'm putting it down to my alkalinity level being 55/65, but when I try to increase the alkalinity level to within range it sends my pH level sky high! then when I dose the pH it sends my alkalinity low again feel like I am going round in circles using lots of chemical and getting no where!! any advise?

Hi Louise. pH and TA can be frustrating, but you can do it. It does take some time because of the their nature, being so closely tied together. TA buffers the pH.

Add the acid around the per perimeter of the pool with the pump on then retest in 8 hours. To raise the TA, add baking soda in the deep end with the pump motor OFF for 4 - 5 hours, then turn the pump on and allow to filter for 8 hours, then retest.

60 Pppm TA is really not that bad. The range is 80 - 120 ppm but don't lose sleep over it.


Feb 24, 2017
Hi levels of acid
by: Mikethank you Robert

Thank you Robert for your quick response I did the refill last year and you are correct the acid level was at 30 I have not used any tablets since then I have my water checked at least once to twice a month it always seems to go up it has me baffled.

When dealing with pool chemistry we need to remember that the water changes when something is added to it. The only way to increase the CYA is to add some product that contains CYA like the products that were mentioned earlier.

It might be you used some type of granular stabilized chlorine such as dichlor or trichlor. It's sold as "shock" but you NEVER want to use that kind of chlorine on a weekly basis. Only when the CYA is low or for black algae. It's impossible for the CYA to increase, and add no CYA at the same time.

Or it could be that someone is putting stabilized chlorine in your pool without your knowledge, but it all leads back to the fact that in some manner, an excessive amount of stabilized chlorine or liquid/granular CYA was put in the pool at some point.

Once you get the CYA back down in range, as was said, only use liquid and stay away from any kind of granular chlorine.

Feb 24, 2017
Cyanuric Acid High
by: Mike

I have a Inground 14,000 gallon pool 2 yrs old I have already had to drain last year for high acid and again this year it is already at 99 ppm.

I do not use chlorine tablets liquid only.What could be the cause any help in this matter would be appreciated. The pool is in AZ.

Hi Mike. We need to remember that pools don't act, they're acted upon. Your fill water probably didn't have any CYA in it during the refill, so that needs to be our starting point.

If the CYA was 0 at the time of the refill, and now it's 99 - 100 ppm, then CYA had to be introduced into the pool at some point, whether through tabs, granular dichlor or trichlor chlorine, or the addition of liquid or granular CYA.

The only other alternative is a false positive reading, or the reading was not taken correctly.

With a CYA that high, unfortunately, you're going to need to do a 1/2 - 2/3 drain and refill to reduce the CYA to the proper level of 30 - 50 ppm and never use any kind of stabilized chlorine. Liquid can handle 99% of your needs.


May 18, 2016
Raising Alkalinity without raising PH
by: Barbara

I have a 12300 gal above ground pool with Pebble Tech Sheen finish. It's 3 years old. I have been told by Pebble tech to keep the TA at 90 and PH at 7.6.

My current TA is 70 and PH is 7.7. When I add baking soda to raise the alkalinity the PH also goes up.

Should I be adding baking soda when my pump is not running? I'm a little confused after reading your info on this issue.

How do I raise the TA without raising the PH?

Hi Barbara. You should have the pump off and then add the bicarb. Let it sit for 3 - 4 hours then turn the pump back on, allow to filter for 8 hours, retest, and make another adjustment. yes the bicarb will also affect the pH to a slight degree. This will be a process that may take a few days to resolve. There is no magic bullet to high TA and pH. It will take a little time to stabilize.


Jan 20, 2015
Total Alkalinity and pH Levels
by: Bill Pike

After my question to you on this same subject of total alkalinity and pH levels a few weeks ago, I did looking around and came up with a lot of information on just why the pump needed to be turned off to raise the TA.

Got into all sorts of stuff about positively charged ions and such, way too much information.

Printed out two pages of what looked like college level math. Simply put it worked like a charm, got my TA up where I wanted it (raised it 80ppm) and the pool pH levels came up from 7.2 to 7.4 (just where I wanted it to be)

Thanks again for the help.

Thank you Bill for the follow-up and comment. I know there's alot of information floating around on the web about the best way to do this or that when it comes to swimming pool chemistry and pool maintenance tips. Most of the time these people are well meaning and they may have been in the pool industry for some time.

Then there are those who are self-proclaimed experts. They read up on the most current information, use big $100 words, and make themselves out to be something other than they really are.

That's why I said it's important of who do you listen to.

Good luck with your pool and have a great Summer


May 26, 2014
Thank you!
by: Amy

I just wanted to say thank you for taking the time to share your expertise with those of us just trying to have a swimming pool in our yards! I

I am grateful for your information and opinions. And God bless you for saving your local Y so much money! What a blessing that is for them. Well done :)

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