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Whenever your pool has a powerful chlorine smell, it can indicate high amounts of bacteria in the water. As the chlorine bonds with the contaminants, it creates combined chlorine. This can break down the chlorine in your water, so your pool isn’t clean.

Shock is simple to use, but you’ll want to ensure you test your chlorine level. Before adding more chlorine or shock, see how the free chlorine level in your water stands.

If you want to get your pool smelling better and looking better, keep reading!

How Should You Add Shock to Your Pool? 

Before adding pool shock to your pool water, you need to test the water’s chemical levels. Use a chemical test kit to determine your pool’s current levels of free chlorine.

Free chlorine levels determine how much shock your pool needs to eliminate the contaminants. As bacteria build up in your pool water, it forms monochloramines or chloramines. This is a chemical reaction between the pool sanitizer and the pollutants in the pool.

You want your free chlorine levels to be 1-3 parts per million. As these chloramines build up, it impacts how chlorine works as a sanitizer. If they’re higher than this, your chlorine levels will not be sufficient to eliminate them in the pool.

After testing your water chemistry and determining you have high amounts of free chlorine, you must shock your pool. To prepare your pool shock treatment, follow these steps:

  1. Mix shock in a 5-gallon bucket
  2. Stir until completely dissolved
  3. Run the pool pump
  4. Pour the mixture into the pool water
  5. Keep the pump running for several hours

You should use a test kit to check the free chlorine level within 24 hours after the treatment.

Can You Add Shock Directly to Your Pool Water? 

Most pool shock treatments require you to dilute it before use. This means you should avoid just dumping it directly in your swimming pool. Not only will it be difficult to mix it into the water, but the measurements are based on diluting the chemicals in the bucket of water.

However, this depends on the type of pool shock your using in your pool. The granular shock treatment must be diluted in the water before adding it to your pool water.

Liquid shock treatment doesn’t need to be diluted, though. Granular shock has chlorine in it and is the more potent variety. It’s the better option if your pool has a strong chlorine smell because this indicates a high volume of bacteria and free chlorine.

Although, if you’re seeking a simpler way to add pool shock to your swimming pool, the liquid option is better. Remember that this pool shock isn’t as potent and won’t kill bacteria as effectively.

Should You Add Shock to the Pool Pump? 

You don’t have to add shock treatment to the pump. The best way to add shock to your pool is to pour it into the water and run the pump.

While you shouldn’t add it to the pump, add it to the pool water and run the pump for at least 8 hours. This will evenly distribute and balance the pool chemicals so they do their job correctly.

What’s the Most Affordable Way to Add Pool Shock?

Granular shock treatment is the most affordable option. This is also known as calcium hypochlorite (cal-hypo for short). It increases the amount of calcium in your pool, but also helps balance your pH and other pool chemicals.

This blend has a pH level between 65-73%, and is the most potent variety. It breaks down the bonding molecules in the bacteria and helps return your free chlorine levels to between 1-3 ppm.

The other varieties include sodium monopersulfate and sodium dichlor. Both of these are more expensive and less potent than traditional shock treatments. Pool owners should only select these varieties if they want a quick solution to a minor chemical imbalance.

How Quickly After Adding Shock Does it Start to Clean Your Swimming Pool?

Shocking your pool should take about 8 hours to clear the water and balance the chlorine levels. However, swimming in won’t be safe until 24-48 hours after the treatment.

The time frame can vary depending on whether the shock is chlorine-based pool shock. Some varieties are non-chlorine shock and won’t clear the water as quickly. When you shock a pool, it will take time for the filter system to transfer it through the water.

Within 24 hours, it should kill off the most harmful bacteria. You should test it the day after shocking your pool to see if you added enough.

Do You Need to Clean Your Pool Before Adding Shock? 

You should clean up any debris in the water before you shock your pool, but it’s unnecessary. You can shock a pool without cleaning it, but shock won’t clear up large debris. If you want your pool shock to work and clear up contaminants, you should also clean the debris.

Vacuuming and skimming your pool is a good idea, though. It will help ensure you properly balance the water chemistry and remove chloramines from the water. If things like algae, sand, and other debris stay in the water, they can alter the water chemistry even after shocking your pool.

You can use a pool brush and other pool tools to remove debris from the pool walls and floor.


If your pool is cloudy or has a strong chlorine smell, it might be time to treat your pool with shock. Shock breaks down the molecular bonds of bacteria and other contaminants in the water.

You should shock a pool about every week during the hotter summer months. This is especially true if there’s been a lot of rain displacing the water in your pool.


Is Combined Chlorine the Same Thing as Shock? 

No, combined chlorine is not the same thing as shock. Shock comes in several varieties, some of which are chlorinated and others that are not. Combined chlorine is what’s produced after contaminants alter the pool water chemistry.

It’s a combination of the bacterial compounds in the water and chlorine. Chlorine shock is the best way to break apart the molecular bonds of the contaminants so they no longer alter the free chlorine level.

Can the Sun’s UV Rays Impact Your Shock Treatment? 

Yes, the UV rays from the sun can impact the efficacy of pool shock. High heat and intense sunshine can break down and disrupt the shocking process.

The sun’s rays cause the water in the pool to evaporate and take away up to 90% of the potency of chlorine. Regular swimming and heavy rains can also ruin the power of chlorine and break its molecular bonds.

This can make it so there’s not enough chlorine to kill bacteria and other contaminants in the water.

Heavy rain and bodily fluids add more chemicals to the water and alter the pool’s chemistry. It’s best to add shock to a pool at sunset and when there’s supposed to be clear weather for several days. This will guarantee that the shock has a chance to cleanse the water without environmental disruption.

Can Cyanuric Acid Improve Your Shock Treatment’s Efficacy? 

Cyanuric acid is also known as a pool stabilizer. This helps prevent the sun’s rays from disturbing the potency of your chlorine and shock. Adding these compounds together can improve the overall balance of the water in your pool.

Can Muriatic Acid Improve the Efficacy of Shocking Your Pool?

Muriatic acid isn’t necessary to use with shock, but it can improve how your chlorine works in your pool. If the pool’s pH level is off balance, it can impede how your chlorine cleans the water and encourage bacteria to develop.

Is Granular chlorine shock Better Than Liquid chlorine shock?

Granular chlorine shock is the most potent chemical to keep your pool clean. However, liquid chlorine shock is easier to use and can be added directly to your pool.

Granular chlorine is the better option if your pool is badly contaminated. It’s also more affordable and can keep your chlorine levels in a normal range.

Do You Need to Wear Protective gear When You Shock a Pool?

You should wear goggles to protect your eyes and gloves to protect your hands. Chlorine is corrosive and can seriously hurt you if it gets into a cut or eyes. This is especially true for a chlorine-based shock because it’s very concentrated.