How to Lower Alkalinity in a Pool: Fastest and Natural Ways

Proven methods to reduce alkalinity with chemicals and naturally.
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Last updated: August 18, 2023
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While a high pool total alkalinity does not necessarily affect the swimmer, it does the pool. The most common and physical effects of high total alkalinity in your swimming pool include cloudy pool water, clogged heater elements and filters, and a rough pool wall surface. When your pool’s alkalinity level is above the recommended mark, you would cause a pH lock. Luckily, this is a guide on how to lower alkalinity in a pool.

But even more than that, this article contains the definition of total alkalinity (beginner friendly), a couple of things that can lead to high pool total alkalinity, why you need to reduce pool total alkalinity, how to lower alkalinity in a pool without lowering pH and how you can do so with chemicals, without, and with natural, household ingredients. So if this is what you want to learn and more, stay tuned and see how to lower alkalinity in a swimming pool.

What is Total Alkalinity?

There are tons of definitions of total alkalinity and what it means. While some of these definitions sound science, others are more relatable for the average person. The two sides would be explained. Total alkalinity, also called TA, is the capacity of water to neutralize acid or resist acidification. This is the first part – to be explained.

From basic chemistry, Hydrogen (H+) is the element that makes things more acidic. The more hydrogen ion that is added to a substance – in this case, water – the more acidic it becomes. Therefore in simpler terms, total alkalinity is the rate at which water can eliminate hydrogen ions from water. When total alkalinity is increased, acidity is decreased and pH is increased towards basicity.

The total alkalinity of water is inversely proportional to acidity but directly proportional to pH.

The other definition for TA – and one that is more relatable to the subject at hand – is that it is the ability of water to retain a certain pH level regardless of the additions and subtractions to the water. Not only does total alkalinity neutralize acid but in a pool, it also acts as a buffer meaning that neutralizes base as well. In that case, total alkalinity does not only eliminate (or take H+) but also give it. Note that total alkalinity does not get a pool to the recommended pH level, it only helps to keep the pH within the degree that is desired.

But what about high or low TA? High total alkalinity means that your water’s pH will fluctuate ever so easily even at a slight drop of acid or alkaline material. If you leave your pool with low alkalinity, you would always have to treat your pool for low or high pH too often. As for a high pool TA, it causes a rigid shift in the water‘s pH. That is, you would find it difficult to change the pH of your pool even if it is too high or too low – also not good.

5 Reasons You Have High Alkalinity

Similar to everything that could occur in your pool, there are factors responsible for its occurrence. For alkalinity, 5 factors exist.

Reason 1: Chemicals like cyanuric acid, carbonates, bicarbonates, and so on

How to Lower Alkalinity in a Pool: Fastest and Natural WaysWhile trying to treat a pool’s low pH, many people (which is recommended) resort to the addition of these chemicals to get your pool back to the recommended pH level (7.2 and 7.6). However, until you know how to raise the pH of your pool and leave the water’s total alkalinity; you would be increasing the pool’s TA, especially when using these chemicals. Raising a pool’s pH means you need to eliminate most of the hydrogen ions present in the water by adding carbonates, bicarbonates, hydroxides, and so on.

Reason 2: Hypochlorite for pool treatment

How to Lower Alkalinity in a Pool: Fastest and Natural WaysTaking you a little bit back to chemistry, chlorine works well for the treatment of water. By adding a small amount of chlorine to the water, it releases an acid called hydrochloric acid which kills all the germs you might have in your pool.

But if you repeatedly use hypochlorite (a form of chlorine), you might be tampering with your pool’s total alkalinity.

Forms like liquid chlorine also called sodium hypochlorite, or chlorine shock (calcium hypochlorite) produce hydroxide as a by-product when added to water, and the more OH you have in your pool, the higher the total alkalinity.

Reason 3: High alkalinity water source.

How to Lower Alkalinity in a Pool: Fastest and Natural WaysThis is only reasonable. Even if you have managed to treat your pool and you know how to lower the pH and alkalinity in a pool – which you have done, you could still get high total alkalinity soon. Again, if the source of water for your pool has high total alkalinity, adding this water to your current pool water will tilt the pool’s total alkalinity towards highness.

Reason 4: Evaporation

How to Lower Alkalinity in a Pool: Fastest and Natural WaysThis is not anyone’s fault. Evaporation, for basic’s sake, is the gradual process of water in its liquid form changing or turning to gas/vapor. The primary factor for evaporation in a normal pool setting is the activity from the sun. When your pool water gets evaporated, the chemicals in it are left behind, especially carbonates, hydroxides, and bicarbonates. Recalling the previous points, the concentration of these chemicals will increase total alkalinity.

Reason 5: High pH

How to Lower Alkalinity in a Pool: Fastest and Natural WaysIt is difficult to talk about alkalinity and exclude pH. The two concepts are highly closely related, especially on the topic of your swimming pool. For your pool’s pH level to increase, you would need to add materials made of bicarbonate or carbonates to break down the excess hydrogen ions that make the water acidic. While doing this, you would also be producing carbonic acid and hydroxides in the process which adds to the total alkalinity. In the same way, while you are trying to lower your pH, you could be lowering your alkalinity as well. To test your pool’s pH and alcalinity use one of the best pool test kits.

Why High Alkalinity Is Bad?How to Lower Alkalinity in a Pool: Fastest and Natural Ways

Higher Resistance to pH change

The first stand-out reason high alkalinity is bad for your pool is that there will be greater resistance to a change in the pH of your water. While many would see this as a good thing – your pool’s pH is resistant to easy change, it can be bad for your pool.

Cloudy Water Appearance and Calcium Scaling

The water in your swimming pool will have a cloudy appearance. A phenomenon called calcium scaling would also occur. This happens when the water dumps materials that it has absorbed onto the surface of the pool.

Filter Clogging and Skin Irritations from Swimming

Another effect of high alkalinity aside from cloudy water and calcium scaling is clogged filters. This problem is highly challenging to prevent and/or treat, you could also be faced with skin irritations when you swim in it. So while you can be excited about your pool’s pH remaining balanced for a while, too much deposit of carbonate, bicarbonate, and hydroxides can still affect your pool’s water and your swimming experience.

How to Lower Pool Alkalinity

Use Muriatic acidHow to Lower Alkalinity in a Pool: Fastest and Natural Ways

A muriatic acid is a different form of the famous hydrochloric acid. The acid is strong and better – corrosive. Though it sounds like an acid that can only be found in the lab, you can find muriatic acid in many supply stores or even in your garage/storage room.

  1. To use Muriatic acid, start by kitting up, Wear your gloves because you wouldn’t want the acid to come in contact with your skin/hands. Also wear long pants, goggles, and a face shield if possible.
  2. Turn off your pool’s pump and wait an hour after this has been done to keep the water still.
  3. Test your pool’s total alkalinity and see how much difference it has from the recommended TA of a pool (which is between 80 and 120 ppm).
  4. Pour the needed amount of muriatic acid into your pool (preferably the deepest part) then leave for about another hour.
  5. Turn on the pool’s pump to allow the acid to settle and spread across your pool. Then test your pool again. If it is not yet at the recommended range, repeat the process.

Use Dry Acid (Sodium Bi-sulfate)

How to Lower Alkalinity in a Pool: Fastest and Natural WaysUsing dry acid will quicken the process and help you see results faster – especially if your TA is way too high. Other names you might know of dry acid as pH decreaser, pH minus, pH reducer, pH down, acid salt, or sodium bi-sulfate. Note that the use of dry acid will lower both your TA and pool’s pH.

  1. Test your pool to know how far away you are from the recommended range of TA
  2. Use the product’s imprinted directions to know how much dry acid to add to your pool
  3. Fill up a bucket with water (about 3/4 of the bucket will do) and add the required sodium bi-sulfate.
  4. Use a stick (wooden NOT metal) to stir the solution and dissolve any granules that could remain.
  5. Pour the solution into the pool making sure you cover all the pool’s area (start from the deepest part).
  6. Retest and repeat the process if necessary.

How to Lower Alkalinity in a Pool without Chemicals

There are four things you can try if you want to know how to lower alkalinity in a pool without chemicals.

Partial Drain

How to Lower Alkalinity in a Pool: Fastest and Natural WaysBy draining your water a little bit, you can alter your pool’s chemistry. However, while doing this, test that the source water doesn’t have a high alkalinity else you will make things worse. Also, don’t drain out a lot of water at once (it must not be up to 1/3 of the pool’s volume). Exposing some of the pool’s inner structure to sunlight can cause them to chip and leak more chemicals into the pool. Do this gradually and you should be able to lower your pool’s TA.

Cover Your Pool

How to Lower Alkalinity in a Pool: Fastest and Natural WaysThis eliminates the factor of evaporation that can cause a higher TA in the first place. Also, it helps to keep debris out of your pool (which tends to alter your pool’s pH level as well). If you are going to be swimming in your pool, getting a proper pool cover is recommended, so read our reviews on the best pool cover reels to exclude evaporation!

Lemon Juice

How to Lower Alkalinity in a Pool: Fastest and Natural WaysLemon is another tool when working on how to naturally lower alkalinity in a pool. Lemon juice is on the high side of the pH scale with a pH level of 2-3. Since it is highly acidic, it quickly lowers alkalinity and pH. But ensure that you keep the quantity to a minimum. Though lemon juice is acidic, it is alkalizing (it produces alkaline byproducts). While pouring it, also ensure that you run the pool pump.

Pour Acidic Rainfall into the Water

How to Lower Alkalinity in a Pool: Fastest and Natural WaysFinally, pouring acidic rainfall will alter your pool’s alkalinity and pH. You can either open your pool when there is a rainstorm (only when there is a rainstorm), or you collect the water and pour it into your pool (if your pool is indoor).

How to Lower Alkalinity in a Pool without Lowering pH

How to Lower Alkalinity in a Pool: Fastest and Natural WaysFrom the above, it can be established that using chemicals and many to lower your TA will affect your pool’s pH as well. To ensure that you keep your pH level within the recommended range, you can try these two ways:

Turn on Your Pool’s Air Features

By turning on your jets or your pool’s pumps, you would be able to lower your alkalinity without touching or altering your pool’s pH. This is only advisable if you have a proper pool pH level. Still don’t have one? Pick one of the best pool filters with our in-detail reviews.

Use Soda Ash to raise your pH level

In the case that you already have a lower pH, you can increase it using soda ash or sodium bicarbonate. This is a better option since it has little effect on the total alkalinity of your pool.


How to lower alkalinity in a saltwater pool?

Saltwater pools already have high total alkalinity and therefore to lower the alkalinity in them, you need to alter the pool’s chemistry and add more hydrogen ions. You can do this by adding dry acid or muriatic acid every other week with frequent water testing until the desired range is achieved.

Does baking soda lower alkalinity in a pool?

Baking soda does the opposite of lowering. It is one of the major factors responsible for raising the total alkalinity of a pool. It is also a driver for increasing a pool’s pH so if you are planning to use baking soda to lower your pool’s alkalinity, you would be making things worse.

Final thoughts

From the above guide, it can be withdrawn that while making pool owners might not be aware of a pool’s total alkalinity, it is highly related to the pH of a pool (but not the same). Where pH directly talks about the pool’s level of acidity or basicity, TA is about the pool’s capacity to maintain (give and take) hydrogen ions in the water. Though most methods that help to lower alkalinity in a pool affect a pool’s pH, there are other options available if you desire to know how to lower alkalinity but not pH in a pool. In general, the steps on how to lower the alkalinity in a pool are to use muriatic acid and a dry acid. More natural methods include draining the pool, covering the pool, adding lemon juice, or pouring acidic rainfall into the pool.

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