What Does It Mean to Shock a Pool?

Pool shocking is a process that involves adding chemicals — whether chlorine or non-chlorine — to the water in order to keep it balanced and raise the free chlorine levels.

The purpose of shocking is to destroy any harmful bacteria, combined chlorine, or algae that could be lingering in your pool.

What Is Pool Shock?

The three main types of chemicals used in pool shock are calcium hypochlorite, sodium di-chlor, and potassium monopersulfate — don’t worry, there won’t be a spelling test!

These chemicals oxidize and sanitize the water, making your pool cleaner and healthier.

What Is Free Chlorine?

The amount of active chlorine that is working to disinfect your pool’s water is known as free chlorine.

What Is Combined Chlorine?

Combined chlorine — also known as chloramines — refers to chlorine that has been combined with ammonia present in your water. This ammonia can come from sweat, saliva, urine, and other substances. While these chloramines remain in your water, their ability to sanitize is significantly lower than free chlorine.

What Is Total Chlorine?

Total chlorine is simply the total amount of chlorine in your water, including free chlorine and combined chlorine.

How to Shock a Pool

Test the Water

Before beginning the process of shocking, it is important to check the chemical levels of your water. Finding your free chlorine and combined chlorine levels will determine how much chlorine you must add to the pool in order to properly oxidize harmful contaminates and keep the water safe for swimmers.

Pool shock will be most effective in a pool with a pH balance between 7.2 and 7.4.

Calculate How Much Pool Shock You Need

Put on your thinking cap, it’s time to calculate the amount of shock your pool needs! For many pool shocking products, the general rule is 1 lb per 10,000 gallons of water.

However, we highly recommend reading the instructions on your product first to ensure proper calculation — each product is different!

Put on Safety Equipment Before Handling Chemicals

Pool chemicals can be extremely dangerous if handled incorrectly. These chemicals can cause extreme damage to your skin and eyes if exposed. For this reason, proper protective equipment is necessary. Be sure to wear gloves, eye protection, long sleeves and pants, and exercise caution when handling chemicals.

Mix Pool Shock in a Bucket

While certain products can be added directly to your pool, many shocking products must be mixed with water before use. Read the instructions on your product carefully and mix it in a large bucket before adding it to the water. We find this also helps avoid calculation mistakes.

Turn on the Pool Pump (& Keep It Running)

A common mistake made when shocking a pool is forgetting to turn on the pool pump. Your pump is an important part of this process, as it helps disperse the pool shock across your water. Once the pump is on, leave it running for several hours in order to allow the product to reach the entire pool.

Tip: This step can be easy to forget, so we recommend turning the pump on before adding the shock to your pool!

Pour Mixture into the Pool

Now that you’re wearing your safety equipment, you’ve premixed your shock, and the pool pump is turned on, it’s time to add the mixture to the water. Do this carefully to avoid splashing, and pour around the edges of your pool.

Test the Water Again After a Couple Hours

Once the mixture has had time to disperse (at least 6 hours), it’s time to test your water once again. Adjust levels as needed, and avoid swimming until the chlorine level has reached 1 to 3 PPM.

How Often Should You Shock Your Pool?

Now that you have an understanding of the pool shocking process, how often should you incorporate this into your pool maintenance schedule?

The frequency at which you shock your pool can vary depending on several factors, including how often you use the pool and the weather forecast. If you swim nearly every day, you should be shocking your water every week. If you’re down to a once-a-week swim, shock the pool every other week.

Keep an eye on your water and complete an additional round of shocking:

If you’re experiencing a heatwave.
After heavy rainfall.
Before opening or closing your pool for the season.
After a gastrointestinal accident.
If you smell an excessive amount of chlorine.
Your eyes and skin become irritated.

Read More: How Often Should I Shock My Swimming Pool?

When Can I Jump in the Pool Again After Shocking It?

The whole family is itching to get back in the cool, crystal-clear water after shocking it — but when is it safe to do so? To be safe, we recommend waiting 24 hours before diving back in. If you want to be even safer, continue testing the water until the free chlorine levels reach 3 PPM or less.

What is Double or Triple Shocking a Pool?

There are times when a single dose of pool shock won’t cut it. When dreaded algae find their way into your water, you need a stronger solution. If you catch algae growth in the early stages, when the water has turned slightly green, up your dosage to two times the recommended amount. If you’re experiencing extreme algae growth, increase it to three dosages. And if you have a case of black algae on your hands, a quadruple dose is called for.

Disclosure: It is highly recommended you consult with a professional pool service like ASP - America's Swimming Pool Company for any issues like pool algae that arise — especially black algae.

Should You Shock a Saltwater Pool?

It is important to remember that saltwater pools also use chlorine to stay sanitized. As such, regularly shocking saltwater pools is a crucial part of their maintenance needs. We find that granular shocking products work well in saltwater pools.

Stay Algae Free with Professional Pool Cleaning & Maintenance

We encourage all pool owners to take control of certain pool cleaning and maintenance tasks. However, professional services from the experts at ASP - America's Swimming Pool Company can provide reliable and effective services to keep your pool clean and algae-free! If you are experiencing an algae problem, we strongly encourage you to reach out to our team at (866) 253-0455 today!