How To Lower Alkalinity In A Swimming Pool


Maintaining proper alkalinity levels in a swimming pool is crucial for ensuring optimal water quality and the longevity of pool equipment. High alkalinity can lead to various issues such as cloudy water, scaling, and decreased effectiveness of chlorine. In this article, we will provide a step-by-step guide on how to lower alkalinity in a swimming pool.

Understanding Alkalinity

Definition and Role

Alkalinity refers to the ability of water to resist changes in pH levels. It acts as a buffer against acidity or basicity, helping to stabilize the overall pH balance in the pool water.

Ideal Range

The ideal range for alkalinity in a swimming pool is typically between 80-120 parts per million (ppm). This range ensures that the pH level remains stable and prevents issues related to high or low alkaline levels.

Factors Contributing to High Alkalinity

Several factors can contribute to high alkalinity levels in pool water. These include tap water used for filling pools, certain chemicals added during maintenance routines, and environmental factors such as rainwater runoff.

Testing Alkalinity

Regular testing is essential for determining the current alkaline level of your pool. Different testing methods are available including test strips and liquid test kits.

To conduct an alkaline test using test strips:
1. Dip a strip into your pool’s water sample.
2. Wait for it according to package instructions.
3. Compare its color with the provided chart on packaging.
4 Repeat this process regularly at least once every week during peak usage season

This will help you monitor any fluctuations so you can take necessary steps if needed.

Reasons for High Alkalnity:

There are several sources from which high alkanlity may come from:
-Tap Water
-Pool Chemicals

Effects Include:
-Increased difficulty maintaining proper chemical balance within their pools
-Decrease Clarity by clouding water
-Pool Equipment Damage and increased scaling

Symptoms Include:
-Cloudy Water
-Scale buildup on pool surfaces

Lowering Alkalinity

To lower alkalinity levels in your swimming pool, follow these steps:

Step 1: Adjusting pH Levels

It is important to balance the pH of the water before addressing alkalinity. This can be done by using a pH decreaser or adding acid to the pool.

Methods for lowering pH levels include:
– Using dry acid or muriatic acid as directed.
– Following package instructions carefully when adding any chemicals.

Step 2: Partial Drain and Refill

Consider partial draining and refilling your pool if other methods haven’t been effective in lowering alkalinity. This step should only be taken after attempting adjustments with chemicals.

Here’s how to perform a partial drain and refill:
1. Turn off the pool pump.
2. Connect a hose to an appropriate drainage point (sewer drain, garden area).
3. Start draining until desired level is reached.
4. Fill up with fresh water from a reliable source, such as tap water.

Step 3: Using Muriatic Acid

Muriatic acid can effectively lower alkalinity levels in pools but it must be handled with caution due its corrosive nature.

Follow these instructions when using muriatic acid:
1.Wear protective gear including gloves goggles etc..
2.Dilute the muriatic acid by pouring it into a bucket of clean water first(remember always add “acid”to “water”).
3.Slowly pour diluted mixture around edges of the pool while circulating it .
4.Re-test alkalinidy after several hours .

Step 4: Using Sodium Bisulfate

Sodium bisulfate is another option for reducing high alkaline levels in pools.This chemical also requires proper handling procedures ,so make sure you’re taking necessary precautions during usage.Instructions for adding sodium bisulfate to the pool:
1. Calculate the amount of sodium bisulfate required based on your pool’s volume.
2. Dilute it in a bucket of water as per package instructions.
3. Pour the diluted mixture evenly across the surface of your swimming pool.

Step 5: Aeration

Aeration is an effective method for lowering alkalinity by introducing oxygen into the water, which helps to release carbon dioxide and decrease alkaline levels.

Different methods of aeration include:
– Installing waterfalls or fountains in your pool.
– Using air compressors or aerators specifically designed for pools.

Tips for maximizing aeration in a swimming pool:
– Positioning air nozzles near areas with high alkalinity levels.
– Running aerating devices during peak sunlight hours when algae growth is at its highest.

Retesting and Maintenance

After making adjustments to lower alkalinity, it is important to retest the levels using test strips or liquid test kits.The recommended frequency depends on factors such as weather conditions and bather load .

Additional tips for maintaining balanced alkalinity levels over time include:

1.Regularly cleaning and maintaining your filtration system
2.Balancing other aspects of water chemistry including pH, chlorine levels, and calcium hardness .
3.Ensuring proper circulation by running your pump regularly .
4.Consulting with a professional if you’re experiencing ongoing issues with alkalinity control .


Maintaining proper alkalinity in a swimming pool is crucial not only for optimal water quality but also to protect equipment from damage caused by high alkalininty . We have provided step-by-step instructions on how to lower alkalinity , ranging from adjusting pH levesl , partial drainning refilling ,using muriatic acid or soduim bicarbonate ,and implementing various forms od aerobic technologies . By following these guidelines ,you can ensure that both youe alkanity range and your pool water remains balanced for a more enjoyable swimming experience. Don’t hesitate to take action now for optimal water quality and enjoyment.


Q: What is the ideal range of alkalinity in a swimming pool?
A: The ideal range for alkalinity in a swimming pool is typically between 80-120 ppm.

Q: How often should I test my pool’s alkalinity levels?
A: It is recommended to test alkalinity levels at least once every week during peak usage season or if you notice any issues with water clarity or equipment scaling.

Q: Can high alkalinity cause skin irritation?
A: Yes, high alkalinity can cause skin irritation as it can affect the pH balance of the water, making it less comfortable for swimmers.

Q: Are there any natural methods to lower alkalinity in a swimming pool?
A: Aeration through water features such as fountains or waterfalls can help lower alkalininty naturally by introducing oxygen into the water.

Q. Is it necessary to wear protective gear when handling chemicals like muriatic acid or sodium bisulfate?
A.Yes , wearing protective gear including gloves and goggles is essential when handling these chemicals due to their corrosive nature.


  • Sodium bicarbonates: Also known as baking soda, this is a common product used to increase alkalinity in swimming pools.
  • Soda ash: A powdered form of sodium carbonate that can be used to raise the alkalinity level in pool water.
  • Hydrochloric acid: A strong acid that can be used to lower alkalinity levels in a swimming pool.
  • Carbonic acid: Formed when carbon dioxide dissolves in water, it contributes to the overall acidity of the pool and can lower alkalinity.
  • Pool Alkalinity: The measure of how much alkali (or base) is present in the pool water. It affects pH levels and plays a role in maintaining balanced water chemistry.
  • Alkaline water/Alkaline irrigation waters/Alkaline pool water/Alkaline fill water: Water with high pH and elevated levels of alkalinity.
  • Acidic water/Acid with Water/Water to Acid/Acid with Water Source/Dissolution of Water/Water body/Body of Water: Refers to low-pH or acidic conditions caused by an imbalance between total alkalinity and pH levels.
  • Normal level/Ideal level/Rules of Thumb/Common Issue/Natural Range/Correct Range/100–140 ppm range for carbonate alkalinity reading/Nominal Levels/Stable Level/Balanced Pool Water/Swimming Pool Pump Balance/Delicate pH Balance/Purified balance/Additive Equipment/Adequate Time/Moderate Time Ample Time/Sufficient time over time

Related Posts

Avatar photo

Mike Hunter

Mike is the owner of the local pool shop. He's been in the business for over 20 years and knows everything there is to know about pools. He's always happy to help his customers with whatever they need, whether it's advice on pool maintenance or choosing the right chemicals. He's also a bit of a pool expert, and is always happy to share his knowledge with anyone who's interested.

Leave a Reply

Your email address will not be published. Required fields are marked *