How to Shock a Pool

shock pool

Owning a swimming pool comes with some important responsibilities – most importantly, safety, maintenance, and regular cleaning. Shocking your pool is a method of pool care that works to dissolve algae, bacteria, and other unwanted buildup that can ruin your pool party. 

If you’re dealing with cloudy water, buildup may be the culprit, so read on to learn how to shock your pool. 

What is Pool Shocking?

‘Shocking’ a pool has nothing to do with electricity. The term refers to adding chlorine or other chemicals to a pool to eliminate algae growth, bacteria, and combined chlorine molecules that can build up in the water (called chloramines). Here are a few common pool contaminants that lead to buildup and cloudy pools:

  • Sweat and body oils
  • Heavy rains
  • Leaves and debris
  • Urine

Pool owners should plan on shocking their pools once every week during the warm season to keep things clean. 

You can shock your swimming pool with liquid chlorine, granular chlorine, or non-chlorine-based pool chemicals. 

Materials Needed to Shock Your Pool

Here’s what you’ll need to shock your pool at home:

  • Pool test kits or test strips. Get some test kits that will measure the chlorine and pH levels of your pool. Testing will ensure you add the right amount of shock and that your pool’s chemical levels are balanced before and after shocking.
  • Gloves, long sleeves, and safety goggles. Safety first!
  • Liquid, granular, or non-chlorine pool shock. If you have a saltwater pool, make sure you’re using a type of pool shock that’s specifically designed for saltwater use.
  • A pH reducer (or increaser). Shocking your pool will be most effective if the water’s pH is between 7.4 and 7.6. You can purchase pH packs at most pool supply stores to adjust the levels as needed.
  • A 5-gallon bucket, if you’re using granular chlorine. Many varieties need to be mixed in with water before application to the pool.

How to Shock Your Pool With Chlorine

Pool chlorination
Photo Credit: Isai Hernandez / Canva Pro / License

Shocking your pool is a relatively straightforward process. All you’ll need is the proper materials and some time to sit outside by the pool. 

Step 1: Put on Safety Gear

You’re about to handle some chemicals, so equip your safety gear.  

Step 2: Test the Pool

When the sun goes down, put on your goggles, long sleeves, and gloves and get out your pool test kit. This will allow you to test the pool to shock it effectively by adding enough chlorine.

When you run a test on your pool for shocking purposes, you’re looking for a few key numbers:

  • Total Chlorine (TC): The total amount of chlorine in your pool. Most pH kits will measure the total chlorine and free chlorine in your pool.
  • Free Chlorine (FC): The amount of chlorine currently disinfecting the water. The ideal free chlorine level for safe pool use is between 1.0 and 3.0 ppm (parts per million). 
  • Combined Chlorine (CC): Also known as ​​chloramines, combined chlorine is the amount of used chlorine in your pool that is attached to contaminants. Combined chlorine is no longer sanitizing the pool. It can be calculated by subtracting the amount of free chlorine from the total chlorine. 
  • Acidity, or pH levels of your pool. Proper pool acidity for swimming is generally between 7.2 and 7.8 on the pH scale (ideally between 7.4 and 7.6). Any lower or higher than this range can cause irritation and burning. 

If your free chlorine count is below 1.0 ppm, it’s time to shock your pool. Ensure your pH levels are in the right range before shocking. 

Step 3: Add Pool Shock

Refer to the shock’s packaging for directions on how to measure the appropriate dosage per 10,000 gallons of water. For example, the product you’re using might call for 1 pound of shock per 10,000 gallons of water to raise the ppm by 1.  

If you’re using granular chlorine, you’ll need to pre-mix your pool shock before adding it to the pool. Once you’ve measured the dosage, mix it with 2 to 3 gallons of pool water in a 5-gallon bucket. Pour the mixture around the pool’s perimeter and wait for it to take effect.

If you’re applying liquid chlorine, you likely won’t need to mix it in a bucket of water. Simply add the appropriate amount of liquid chlorine directly into the pool. 

Pro Tip: Always run the pool pump when adding shock to the pool. 

Step 4: Let It Sit

Don’t dive in right after applying pool shock to your pool! After shocking, let your pool sit for 24 hours, then test the water again. If the free chlorine level is between 1.0 to 3.0 ppm, your pool is ready to use.

How to Shock Your Pool Without Chlorine

Non-chlorine pool shock can’t get rid of algae, but it’s a good supplement for shocks that break down oil and organic matter. It won’t affect your pool’s chlorine levels or kill bacteria and algae. It’s an ideal option for pool owners who want to clear up murky water and use the pool soon after. Most varieties will allow you to jump back in in as little as 15 minutes.    

Non-chlorine pool shock won’t break down in the sunlight’s UV rays or damage in-ground pool liners like chlorine does, and it also doesn’t lose its efficiency over time as easily. 

Here’s how to use non-chlorine pool shock: 

Step 1: Safety First

Non-chlorine pool shock isn’t as harmful to your skin as chlorine can be, but that doesn’t mean you can skip the safety gear. Get ready to shock your pool by putting on gloves, goggles, and long sleeves. 

Step 2: Calculate How Much to Use

Refer to the package directions and your pool’s size to determine how much non-chlorine pool shock you’ll need for your pool. Shock calculations will vary based on the type of shock you purchase and the size of your specific pool. Most non-chlorine products call for 1 pound of shock per 10,000 gallons of water. 

Step 3: Pre-Mix Your Pool Shock

You can technically put non-chlorine pool shock straight into your pool, but it’s better to pre-mix a solution in a 5-gallon bucket. Scoop some of your pool water into the bucket and mix the pool shock in, just like you would with granular chlorine. 

Step 4: Add Pool Shock

Get the pool pump running, then add your pool shock solution to the water around the perimeter, focusing on areas with jets to disperse the shock more quickly. Then, after 15 minutes, test the chemistry levels of the pool to make sure the numbers look right and you’re good to go.

Why Shock Your Pool?

Pool shock
Photo Credit: Pepifoto / Canva Pro / License

Shocking your pool isn’t just about achieving a clear appearance. It’s an important way to prevent buildup that can negatively affect your health.

Left untreated, pools can breed disease-causing bacteria, while chloramines can cause skin and eye irritation, and even form gas that causes respiratory problems for swimmers.

When to Shock Your Pool

chlorine test
Photo Credit: Mustafagull / Canva Pro / License

In the wintertime, decreased use and exposure mean you won’t have to shock your pool as frequently as in the summertime. Shock your pool once a month in the cold season, and avoid the use of chlorine tablets during wintertime.

When your pool is in use, shock the pool once every week. In addition to weekly shocks, shock your pool whenever an event causes the ppm to dip below 1.0, such as after a pool party, contamination, or rainstorm. 

Shock your pool in the evening after the sun has set. Otherwise, the sun’s UV rays will deplete the chlorine, causing your shock to sanitize less effectively. 

Can You Over-Shock a Pool?

It’s unlikely that you could add enough shock to your pool to make it dangerous for use, but it’s still important to follow the directions to determine the correct amount. Always wait for your pool to return to safe chlorine levels before using it after applying shock.

Do I Need to Shock My Saltwater Pool?

Both chlorinated and saltwater pools use chlorine to sanitize the water. A saltwater pool generates its own chlorine, so you won’t need to manually add chlorine as often as you would a chlorinated pool. However, you’ll still need to closely monitor the chlorine levels and ensure the free chlorine remains between 1.0 ppm and 3.0 ppm. 

Just Keep Swimming

If you don’t want to add pool shock to your weekly chore list, consider hiring a company to maintain your pool for you. On average, pool owners spend between $1,064 and $1,800 per year for professional pool service

Want to keep the rest of your yard looking sharp and avoid leaves piling up in your pool? A local lawncare company will help your yard stay clean without the stress.

Main Image Credit: Isai Hernandez / Canva Pro / License

Annie Parnell

Annie Parnell

Originally from the Washington, D.C., area, Annie Parnell is a freelance writer and audio producer based in Richmond, Virginia. She is passionate about gardening, outdoor recreation, sustainability, and all things music and pop culture.