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How To Lower Total Alkalinity in a Swimming Pool: No Extra Cost

Updated on June 20, 2017
Barack James profile image

Barack is a chemical engineer who has a knack for pool chemistry. He has been in the pool maintenance industry for 8yrs & has extreme skills

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How To Reduce Total Alkalinity and pH Levels: No Extra Equipment

This article is suitable for individuals who need to reduce excess Total Alkalinity and pH down to the recommended levels for a swimming pool.

If you have a cloudy swimming pool water or pool algae breakout, please click the links and find a complete guide on how to resolve each problem.

Also, if you have a low pool alkalinity and it's worrying you up, you better pick up Alkalinity Increaser and raise Total Alkalinity up to the recommended levels, and do it fast to avoid pool corrosion that may occur due to low alkalinity levels.

Now, let us begin: If you have tried all the methods you know to lower total alkalinity (TA) in your pool, but things seem to be getting worse, then you have come to the right place.

It's not costly to lower total alkalinity from high levels to recommended levels since there is no extra equipment required: All you will need to lower your pool's TA level are muriatic acid, very accurate pool water test kit, and a natural process known as aeration. (Don’t tense. It's not rocket science.)

Chances that you will succeed in lowering the level of Alkalinity in your pool largely depends on the acid that you will use. I like using Sunnyside Muriatic Acid since it is very fast in reaction and speeds up the process of reducing the total alkalinity.

It's also important to know that when total alkalinity gets too high in a pool, the pH level in your pool will also rise up past the recommended levels, and consequently, this process is basically about reducing both the levels of TA and pH.

But since your pH level will drift much lower when strong acid like muriatic is added, aeration is needed to restore the recommended pH levels naturally without adding a pH increaser that also increases alkalinity.

Why Does Aeration Increase pH Level?

When you aerate your pool, that means you are exposing the pool water to more oxygen to do away with some of the carbon dioxide present in the pool water. And, we all know that carbon dioxide mix with water to form an acid we call carbonic acid.

Any acid added into water, in this case, pool water, will lower the pH levels. On the other hand, when acid is removed from the water, the pH level will rise. As such, aeration literally removes carbonic acid from the pool water, which then raises the pH levels in the pool water.

I always recommend natural aeration when it comes to raising pH levels since you cannot over aerate your pool, which is a very common issue when pool aeration equipment are used and natural balance may be surpassed.

As a matter of fact, over aeration is dangerous to your pool: You need some carbonate in your pool to act as a pH buffer and to saturate the pool water with some carbonate to help protect calcium carbonate, which is useful in plaster pools since it prevents dissolving plaster.

In a case of over aeration, pH will rise above the recommended levels while calcium carbonate will reduce below the required level. To fix over aeration, you need to check up the pH and calcium carbonate levels in your pool and adjust them as appropriate to avoid any further damage to your pool.

Below, I have included everything I did step by step. It took me two days and two nights (48 hrs) to get the perfect balance of total alkalinity and pH. I used muriatic acid and then aerated the pool naturally without using any aerators such as spa jets, waterfalls, fountains, return pointers, air compressors, or the likes.

This process needs patience as it may take a day, two days, one week, or even longer, depending on how extreme the TA and pH levels are high in your pool.

However, if you need faster results, at the end of this article I have included all the equipment to help speed up the aeration process and how to use them: But extra care needs to be taken to avoid over aerating your pool if you decide to use aerators.

Summary: How to Reduce & Balance TA and pH Levels in a Pool

 
 
Step 1
Take accurate readeings of TA and pH using a reliable test kit.
Step 2
Dilute muriatic acid and distribute it evenly in the pool. Use a pool calculator to get the exact amount of acid needed. Your target TA level should be 100 ppm.
Step 3
Take readings after 6 hours, then after 24, then after 48.
Step 4
Allow the pool water to aerate to help bring up the pH level. The recommended level is around 7.5 ppm or 7.6 ppm.
Step 5 (optional)
Use an air compressor to accelerate the aeration process.

Step 1: Take Accurate Readings of pH and TA in the Pool

I took accurate readings using LaMotte ColorQ Pro 7 digital pool water test kit. From my personal testing, the pH read 8.3 ppm and total alkalinity read 280 ppm. Your readings may be higher or lower compared to mine but that does not matter.

Very Important Note

You need a very accurate test kit for this process. The more accurate your readings are, the easier your work will be. Most of the test strips available on the market are not accurate and will make your job a hell.

Step 2: Set a Target Value for Total Alkalinity

I set the target value of TA at 100 ppm. It is important to note that both the levels of TA and pH reduce when acid is added. A target value of 80 ppm or 90 ppm should be just fine, but I anticipated that the levels of pH will drop way below 7.0 ppm when I add a strong acid, so 100 ppm was ideal for me to give me easy time raising the level of pH later on through aeration.

Use a pool calculator to calculate the exact amount of muriatic acid needed in order to achieve the target value of 100 ppm for TA - or whichever target value you have chosen.

In this step, don't worry too much about the pH. The main aim is to lower the total alkalinity to recommended levels. Later on, you can aerate to raise pH levels.

Step 3: Dilute Muriatic Acid as Directed and Add It to the Pool

The pool I was working on was 20,000 gallons. To get my target value of 100 ppm, I added about 2 quarts of muriatic acid.

I distributed the muriatic acid solution slowly around the pool while the pump was running high to increase the effect.

Some pool managers prefer adding the muriatic acid solution in one spot. Personally, I don't like to do this because acid can damage pool parts when it is concentrated in one region.

Aeration process begins after you add the muriatic acid and the levels of pH and TA have fallen and settled down. During the aeration process, the levels of pH alone will rise gradually until it reaches the recommended level.

You will be watching on the changes in pH level by doing a pH test after every 12 hours until it reaches the right range.

Step 4: Test the Pool Water After 6 Hours

Amazingly, when I tested the water 6 hours later, total alkalinity was reading at 205 ppm from 280 pmm and pH was at 7.6 ppm from 8.3 ppm.

Step 5: Take the Readings After 24 Hours

The following morning at 10 am, around the same time I started the operation a day before, the total alkalinity had gone down to 120 ppm. This was not the target value I set, but I was still impressed since it was already within the recommended value for a standard swimming pool.

On the other hand, pH was getting lower and it was reading 7.1 ppm. This didn't worry me a lot because according to my digital pool water test kit, the lowest it could go was 6.8 ppm, which is still okay and won't be destructive.

Since both chemicals were still within a reasonable range, all was fine for me. So I waited to take my next reading in the evening, approximately 5 to 6 hours later. When I took the reading in the evening, TA was ranging at 106 ppm, and the pH dropped to 6.9 ppm. You can imagine how impressive that was.

This meant that total alkalinity was inching closer to my target value, despite pH going down. Again, don't worry about the pH because you can balance it later using the 'magical' aeration process.

Step 6: Take Final Water Test 48 Hours Later

After two days and two nights of keeping a close watch over the pool, I took the reading in the morning. Total alkalinity was reading 101 ppm — not bad at all. The pH was stable at 7.4 ppm. Remember that even if the aeration process is not complete, the pH level will unlikely rise above the recommended levels because the alkalinity should be within range and no pH increaser is used in this process.

Note

If your results are different from mine, it may be that you are using poor quality test strips. You will have to take accurate readings of TA and pH again. Then use the pool calculator and repeat the entire process until you get your TA and pH in the correct balance.

At what Level do you Maintain your pH

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Overview of Aeration: Balancing Total Alkalinity and pH

Aeration is a complicated chemical process. It involves pointing the returns upwards and running the pump on high to create a surface disturbance, which introduces air. You must go through this process until the perfect natural equilibrium is reached between water and air at the surface. If interested, here is the detailed theory behind the aeration process of balancing pH and TA.

How the Aeration Process Works

  1. You start by adding muriatic acid as needed in the affected pool. Then you must repeat this step until you get a perfect chemical balance. This will lower both the pH and total alkalinity.
  2. In most cases, when total alkalinity goes up, pH will drift up as well. Unfortunately, there is no pool chemical that can raise pH level only without raising total alkalinity - may be soon chemical engineers will invent that kind of chemical:) In other words, if you lower a pH of 8.3 ppm to the recommended level using muriatic acid, the total alkalinity will also reduce but will still remain on the higher side. Likewise, if you lower alkalinity to the recommended level (e.g., from 300 ppm to 80 ppm), the pH level drops way below the recommended level.
  3. If you add a strong acid like muriatic and then add a base like soda ash to raise total alkalinity, it will not work. This is because both chemicals (base and acid) will cancel each other, leaving your pool in the same initial mess.
  4. Aeration is a repetitive process that is done slowly and step by step. Your goal is to use muriatic acid to reach the target value of total alkalinity without letting pH go below 6.8 ppm. If the pH falls, you can raise it without affecting total alkalinity by aerating.

Accelerating the Aeration Process Using an Air Compressor

Using an air compressor will add additional air to create surface disturbance and speed up the process. You can use an air compressor with an end tube that has several tiny holes in it. Place it in the deep end. The small bubbles that escape from the holes produce carbon dioxide, which is released into the atmosphere to accelerate the aeration process. Do this with the pump running high. With an air compressor, it may take only a few hours to get TA and pH back to recommended levels.

Other Recommended Ways to Accelerate Aeration Process

  • Use a degasser to remove carbon dioxide faster.
  • Use venture injectors.
  • Use manifolds with holes.
  • Use a pressure washer aimed into the water to create turbulence.
  • Use return lines that are aimed up (e.g., waterfalls or spillways).

Facts to Know

  • A high TA level has a potential indirect risk of affecting how all chemicals function in a pool. For instance, the pH — one of the most important chemicals in the pool — is hugely affected by total alkalinity. When alkalinity goes too high, the pH will drift to the higher end and this will render all chemicals in the pool useless, including chlorine.
  • On the other hand, when the TA goes too low, the pH will drift down. This is very destructive to the pool structure and equipments, as well as harmful to human health.
  • High total alkalinity is also associated with calcium saturation index (CSI), a process which causes calcium scaling and comes as a result of high pH levels.

Personal Experience

I manage my swimming pool myself and such cases of high pH and alkalinity are not common thanks to my efforts. About a month ago, a close friend of mine who has a plaster pool informed me that he had a huge drift in pH. I came to realize that he was using soda ash to increase the pH whenever it dropped below the recommended level, and baking soda to raise TA.

Soda ash raises alkalinity, just like baking soda does. This caused total alkalinity levels to increase, which in turn also increased the pH. When I checked his pool, it was at 8.2 ppm and was scaling up higher day by day. Total alkalinity was reading well over 280 ppm when the recommended values should be between 80 ppm and 120 ppm. Luckily, the calcium level did not scale as expected due to the calcium saturation index — it was within the expected range of 250 ppm. Calcium scaling causes cloudy pool water.

Conclusion

Total alkalinity should only be lowered when it is causing a significant rise in pH levels, or when it causes calcium scaling through CSI.

To lower pH and total alkalinity, use a strong acid such as muriatic acid, sulfuric acid, or sodium bisulfate, all of which lower both pH and TA, but at different rates. You need to use an accurate pool water test kit that can give you correct readings. If possible, find a software that can help you get exact amounts of dry acid to add into the pool.

This process may take longer than anticipated, depending on how high pH or total alkalinity is, and how low you need to bring them down before the aeration process begins. However, you can always use an air compressor or any other aerator to accelerate the process.

If you have achieved the ideal reading for total alkalinity but the pH is scaling up because the process of aeration has not yet ceased, you can use Borate to keep the pH stable. The recommended level for pH is around 7.5 ppm or 7.6 ppm.

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    • Barack James profile image
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      Barack James 2 weeks ago from Green City in the Sun

      Magnum that is true, Super Floc is the solution for a cloudy water caused by lots of debris. It is perfect for spring start-up when pools have lots of dirt common in the spring seasons. Floc has a fast-acting formula that drops debris to the bottom of the pool for easy vacuuming. Super Floc is also safe for all pool types and works with all filter types.

    • profile image

      Magnum Wessell 2 weeks ago

      Lanea head use a floc such as drop out to settle the cloudy water to bottom then vacuum out

    • profile image

      TT 3 weeks ago

      Hi Lanea,

      Your nitrates are probably off the charts, check those.

      I hate to say it but you are better off starting over if that is the case, draining and refilling. You will follow this cycle all summer adding hundreds of dollars of checmicals and still have nasty cloudy water, I just went through the exact same thing in Illinois.

    • Barack James profile image
      Author

      Barack James 7 weeks ago from Green City in the Sun

      Hi, Lanea Head, from my understanding, your pool is still under control, all you need is an accurate test kit (See:https://hubpages.com/living/Lamotte-ColorQ-Pro-7-D... ) since there is a high chance that the chemicals (PH, CH, TA, etc) are not well balanced in that pool. Also, ensure that your filtration and circulation system is perfect (not stagnant). You can follow this link for more options you can use to identify the cause of cloudiness and how to clear your cloudy pool water: https://dengarden.com/swimming-pools/Cloudy-Swimmi...

    • profile image

      Lanea Head 8 weeks ago

      I just opened our 30,000 gallon above ground pool for the summer.

      It was yucky green with lots if algae. I brushed the walls and the bottom then vacuumed it. Later that night I shocked it (heavily) and put 3 chlorine tablets in the skimmer basket, and poured 2 gallons of liquid chlorine into the water . The next morning the the green was gone but the water was very cloudy. I vacuumed it really well and let the filter do its job for a few days thinking it would clear up but it is still cloudy. Now two weeks later it's still cloudy. Last night I shocked it again using more shocked than needed. I get up this morning and it's still cloudy so I vacuumed it and now I have the filter running. It's not as cloudy as it was to begin with I can see to about my third pool step. The test kit that I use only measures bbr, chlorine, and pH. It says my pH is low and my chlorine is high. Do you have any tips or advice for me? I have for kids that are waiting on this swimming pool and I can't seem to clear it up

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