How To Use Sodium Hypochlorite In Your Pool & Everything Else You Should Know

Written by Michael Dean
May 22, 2023

sodium hypochlorite

One essential factor you must consider when performing pool maintenance by yourself is using the right chemicals to keep it clean. Among the many chemicals you may come across during your tenure as a pool owner is sodium hypochlorite. Sodium hypochlorite is an effective chemical that some people consider for pool treatment.

Below, I’ll provide some insight into sodium hypochlorite’s characteristics, when to use it, how to use it, and more.

Main Takeaways

  • Sodium hypochlorite is more commonly known as liquid chlorine or liquid bleach.
  • You should use sodium hypochlorite at night time, as if you use it during the day, the sun’s UV rays will degrade it.
  • You can add the sodium hypochlorite manually or with a feeder, but make sure you lower your pH levels before you add it.
  • Some safety tips when handling sodium hypochlorite include: do not ingest or inhale it, wear proper protective gear by covering your skin and eyes, and store it correctly.

What Is Sodium Hypochlorite?

Sodium hypochlorite is a compound formed from a chemical reaction between chlorine gas, water, and sodium hydroxide solutions. People also refer to it as “liquid chlorine” or liquid bleach.

Other characteristics include a yellowish tint and a robust chlorine odor. Its pH level ranges between 11 and 13.

When sodium hypochlorite reacts with pool water, it creates hypochlorous acid that sanitizes and oxidizes water to eliminate pathogens.

Depending on how much of the solution you add to pool water, it won’t damage most swimming pool finishes, including:

  • Aggregate
  • Fiberglass
  • Vinyl liner
  • Plaster

When Is It Appropriate to Use Sodium Hypochlorite in Your Pool?

Ideally, you should add sodium hypochlorite to your pool at night. This time works better than doing it during the day because of the lack of energy from ultraviolet rays. Exposure to UV light degrades the sodium hypochlorite quickly since it’s a type of unstable chlorine.

Since daylight hours tend to increase as spring transitions to summer, the temperatures tend to peak the more prolonged the sun is out.

During the day, your pool becomes a breeding ground for all types of germs and substances. Examples might include sweat, sunscreen, algae, urine, dirt, and debris. Pool occupants are most active during the day, so it’s not surprising how much contaminants can enter the water.

If you need to shock the pool before adding the sodium hypochlorite, it would be best to wait until dusk to get the best results. For more effective results, removing as much debris from the water’s surface would also be wise to simplify your sanitation process.

Champion Pool Shock Liquid Chlorine (12.5% Concentrated Strength)

This shock from Champion is an easy-to-use liquid chlorine perfect for getting rid of algae and cloudy pool water.

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How to Use Sodium Hypochlorite in Your Pool

As a diluted solution, you can add your ideal amount of sodium hypochlorite to your pool in several ways.

Adding It Manually

When applying it manually, it would be best to add it to the deepest end of your pool, away from metal ladders and obstacles, to prevent unstable chemical reactions.

Some people might consider adding stabilizers, such as cyanuric acid, to the water to extend how long the chlorine lasts as it cleans. I believe this might be an excellent choice for people who don’t want to add large doses of sodium hypochlorite.

It would be best to pour the solution closer to the water’s surface when adding it manually. Slowly pouring it can prevent uneven distribution if your pool has more gallons of water in it.

By pouring it slowly and closely into the water, you prevent the solution from accidentally splashing into your eyes, skin, or mouth.

Adding It With a Feeder

Another option you can consider is by using positive displacement feeders to pump and distribute the chemical. This method can help you save time and energy as you prepare it at night.

Before adding your liquid chlorine to the feeders, it would be wise to calibrate them to match their recommended specifications. You should also take this opportunity to check for any signs of wear or damage. Fragile or leaky tubes indicate you should find a replacement as soon as possible.

Neutralize Your pH

Before adding sodium hypochlorite to your pool, you should lower the water’s pH levels to ensure you don’t increase its acidity. While a small dose won’t do much, more significant amounts are more likely to increase this level.

Sodium Hypochlorite vs. Calcium Hypochlorite

Although you can choose between several pool sanitation chemicals to suit your cleaning needs, one alternative to sodium hypochlorite might stand out. Some people know it as “calcium hypochlorite,” while others know it as “bleaching powder.”

Although they perform similar tasks when disinfecting your swimming pool and are soluble in water, some differences set these substances apart. Depending on how often you want to clean your pool and how much of an effect you want from it, you might prefer one chemical over the other.

Liquid vs. Tablets or Granules

Most sodium hypochlorite solutions are in liquid form, have a clear complexity, and have a yellow or green color. Calcium hypochlorite is a solid material that people place in their pool in the form of a white tablet or granules.


As mentioned before, sodium hypochlorite forms after mixing sodium hydroxide, water, and chlorine gas. However, calcium hypochlorite forms after mixing calcium oxide (quicklime) and chlorine gas.

Chlorine Percentage

Sodium hypochlorite typically contains at least 10% to 12% of available chlorine released when disinfecting water. In contrast, calcium hypochlorite’s maximum available chlorine percentage measures around 70% once added to water. Read my article on pool shock vs. typical chlorine for more details on chlorine percentages.

How You Add Them to Your Pool

When adding sodium hypochlorite to your pool, you can pour it into your pool due to its liquid state. For better distribution during a cleaning session, you might prefer pouring liquid bleach into your pool’s automatic filters.

When using calcium hypochlorite for your pool, you have to dissolve its tablet or granules in a separate water bucket before adding it into the pool. As it dissolves, you need to stir it to dilute the chemical. If you decide to place it in a feeder, you might need to monitor its distribution to avoid clogging.

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Safety Precautions

Although sodium hypochlorite is an effective chemical for cleaning your pool, there are several factors you must consider when using or storing it safely. Understanding these factors can reduce your exposure to its health hazards.

If any of these incidents occur, have its product label or material data safety sheet on hand when calling medical professionals for treatment insight.


As a corrosive substance, it would be best to avoid ingesting sodium hypochlorite for several reasons. When ingested, it causes severe corrosion and damage to your gastrointestinal tract, including your mouth, throat, and esophagus. It also leads to poisoning.

It would be best to contact poison control in situations where somebody might ingest sodium hypochlorite. It would also be wise to keep it away from young children or pets.

Swallowing water and diluting it with milk or antacids is an effective solution for neutralizing the toxic substance before poison control arrives.


Inhaling sodium hypochlorite fumes can lead to irritation in your lungs and nose. Higher exposure to it can result in severe bronchial irritation and pulmonary edema (fluid build-up in the lungs). To avoid these potentially fatal conditions, limit your time around the chemical and get some fresh air, or wear a mask while using it.

Eye and Skin Contact

When handling sodium hypochlorite, it would be best to use gloves and eye protection as you apply it in your pool. It can irritate and burn your skin when it touches exposed skin, leaving rashes and blisters. If it gets in your eyes, you risk burning, irritating, or damaging your eyes.

When it touches your skin or eyes, rinse them with water for 15 to 20 minutes. It would also be best to remove contaminated clothing to prevent it from seeping into your skin. After rinsing the affected areas, contact a medical professional or poison control center to receive further treatment advice.

Before letting people swim in a pool cleaned with sodium hypochlorite, measure the pool’s pH levels to ensure its chlorine levels measure to four parts per million (ppm) or less.

Store Your Sodium Hypochlorite Safely

As a corrosive material, sodium hypochlorite can create damage when exposed to other chemicals or metals. Although it isn’t combustible, its properties as an oxidizer can enhance the combustion of other materials. This reaction produces toxic sodium oxide and chlorine gas.

Examples of materials that are incompatible with sodium hypochlorite include:

  • Hydrochloric acid
  • Acid-based brick or concrete cleaners
  • Metals (including copper, nickel, cobalt, iron, aluminum, and carbon steel)

Ideally, it would help if you stored sodium hypochlorite in airtight containers placed in well-ventilated areas. Sodium hypochlorite decomposes when exposed to the sun’s ultraviolet rays, so it would be wise to keep it away from open light sources.

Sodium hypochlorite remains stable in cool storage areas in temperatures around or below 60°F. If you place it in hotter temperatures, its quality degrades. The same goes for other pool chemicals. Head over to my post on how to safely store pool chemicals for more details.

Wrapping Up

Sodium hypochlorite is an effective solution for self pool maintenance and cleaning. I think it’s an excellent choice for pool owners seeking affordable chlorine that suits their needs.

Questions? Shoot me a note.

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