How to Shock Your Pool The Easy Way

Michael Keenan


Pool Water Chemistry

Are you looking for a simple way to keep your swimming pool clean and perfectly balanced? Super chlorinating, also known as “shocking,” is one of the best ways to do this.

In this guide, I’ll explain everything you need to know about shocking a swimming pool in plain and simple terms. It’s an easy and effective process that should be done on a weekly or bi-weekly basis – I’ll tell you all about it!

Plus, I’ll give you tips on when and how to shock your pool with the different types of chemicals available. Whether you’re a first-time pool owner or an experienced one, this guide is perfect for you!

how to shock a pool

Quick Answer:

Shocking (or super chlorinating) a pool is an easy and effective way to keep it clean and balanced. You need to determine the amount of chlorine in your pool, do some math to figure out how much shock you need, add it while making sure you are safe, then wait 8 hours if it is a chlorine-based shock or 15 minutes for non-chlorine before swimming.

Shocking should be done at least once a week to prevent contaminants from building up. With this guide, you can make sure your pool stays healthy!

Types of Pool Shock

There are several chemical sanitizers that you can use to shock your pool. The most popular shock treatments are chlorine based – but there are chlorine-free alternatives that work well.

Calcium Hypochlorite – Cal Hypo

Calcium hypochlorite shock is the cheapest one (and the most widely used) but it does not last as long as the others if the pool is in sunlight. It is seen as unstabilized chlorine – read my guide for more details.

It is strong and dissolves quickly so it’s best to apply it at night. It is available in the form of granules. So, you must dissolve it before you add it to the pool.

Sodium Dichlor Shock

Sodium dichlor is another option that gives a longer-lasting shock. This is also available in granular form and depending on the brand, you might have to dissolve it beforehand.

It takes more time than calcium hypochlorite but that is why it will last longer. And since it doesn’t have calcium in it, the water doesn’t turn hard. This is also good to be used only at night.

Lithium Hypochlorite Shock

Or you could get lithium hypochlorite. This is good if you have high levels of calcium in the pool (hard water) – because it doesn’t contain calcium. Check for the calcium levels of your pool water using a test kit. This one is the most expensive type of pool shock.

Typically, you must wait eight hours after adding any of these chlorine mixes. But you can pick a non-chlorine shock if you want to be done with it and get to swimming in about 15 minutes.

Non-Chlorine Pool Shock

These non-chlorine shocks have potassium peroxymonosulfate as their active ingredient. This shock is oxygen-based rather than chlorine-based and works by oxidizing the pool water and boosting chlorine levels.

It’s great if you need to give a fast shock after heavy use but don’t want to wait overnight to use the tub again. Non-chlorine shock works in around 15 minutes. As always, be sure to test the levels before using the hot tub again.

One drawback of non-chlorine shock is that it doesn’t kill algae very well so if you have problems with algae you might use an algaecide alongside it.

Why Shocking Is Important for a Healthy Pool

Like everything else in your home, your swimming pool also needs intense cleaning as often as you can. That’s because some organisms in the pool do not die when you add regular amounts of chlorine. And some others just grow immune to it over time.

If you are looking for a straightforward answer, here are three reasons to do this.

  • If your pool is outdoors, sunshine breaks down the chlorine you have added and makes you lose about five parts per million every day.
  • Anyone who enters the pool brings particulates like sweat, makeup, and bacteria along. A regular dosage of chlorine is just not enough.
  • After extreme weather or rain, your pool gets diluted and needs a recharge sanitizer.

All these can lead to water quality problems such as green pool water or pool foam. Find out how to fix those issues in my easy-to-follow guides.

How to Prepare Pool Shock

The first step in this process is to determine how much shock is required. For that, you need to measure the existing amount of chlorine in the pool. This can be done with the help of what is called a DPD kit. These kits are available everywhere and measure chlorine in ppm.

Step 1: Fill up the test tube by dipping it 1.5 feet down in the pool. Once the water reaches the fill line, place a chlorine tablet in it. Place the lid and shake the tube to help the tablet dissolve.

Check the color of the water against the chart. This is the free chlorine in your pool.

Step 2: To check the total chlorine in the pool, open the same test tube and add a DPD #3 total chlorine tablet. Close the test tube and shake the tube to dissolve the tablet. Check the color on the chart and write down the value.

Step 3: To get the combined chlorine value, which is the result of chlorine mixing with the contaminants, remove the free chlorine value from the total chlorine value.

For example, if total chlorine is 2.5 ppm and free chlorine is 1.2 ppm, your pool’s combined chlorine is 1.3 ppm.

Step 4: Now take that combined chlorine value and multiply it by 10. This gives you the breakpoint level, which is the amount of chlorine that is needed to break down the combined chlorines in the water.

If you fall short, you will end up not adding enough chlorine and that just makes it worse. In this case, your breakpoint level will be 1.3 x 10 = 13.

Step 5: After finding out the breakpoint level, you must find the desired change amount. This is the measure of how much change you want in the water in terms of ppm. You will get this by subtracting the free chlorine level from the breakpoint level.

Based on that you can calculate the amount of chlorine you need to add. In our current example, that will be, breakpoint (13) – free chlorine level (1.2) = desired change amount (11.8).

Step 6: Now divide the volume of your pool by 10,000 gallons. So, if your pool is 60,000 gallons, divide it by 10,000 gallons and you get 6. Which means you need to change your pool’s ppm by 6.

Check the product and figure out how much of it you need to put in the pool to get that result. All the products will have detailed instructions provided.

Don’t worry if this all sounds too complicated – take your time and work through the calculations. Trust me it’s easy enough!

pool shock

How to Shock Your Pool in 4 Steps

This is actually not a complicated process. You just need to follow the steps carefully.

  • Step 1: Safety first. Put on goggles and gloves before turning your pool on. Protect your skin from the chemicals by wearing long sleeves and pants that can get dirty. Let the water in the pool circulate before you mix the shock.
  • Step 2: Do the math and dissolve the granules in a bucket of water if applicable. Stir it and add the chemical slowly to the pool. Some of them can burn the skin. So, be careful.
  • Step 3: Pour the shock into the pool, moving around the edges. This helps the shock distribute itself in the water. You could add the mix one bucket at a time or use a liquid product for evenness. If you get any of it on your skin, wash it off right away and check its packaging to see if you need to call poison control.
  • Step 4: Check the product to see how long you’re supposed to wait before swimming in it. If it’s a non-chlorine shock, the wait time is somewhere around 15 minutes. If it is a chlorine-based one, it will be about eight hours. Either way, wait till the water is at 3 ppm using the DPD kit before you dive in.
safety goggles and gloves

When to Shock Your Pool

People usually do a deep cleanse only when they see that the water is getting impure. Then what about the germs and contaminants that you can’t see?

Shocking the pool is something you need to do before you spot cloudy waters or see algae growing all over.

Once a week is a good rule to live by. This keeps the contaminants at bay and prevents algae overgrowth.

If you ignore it, you will have to do scrubbing, vacuuming, and even draining. If you do put it off, you must shock the pool when the free chlorine levels drop (below 3 ppm).

It is a good idea to shock your swimming pool after any type of contamination. Something spilled in the pool, pee or pooh in your pool, or an infestation of water bugs in your pool – all can be helped with a shock treatment.

Additional Tips

Throw in your pool toys and accessories after adding the pool shock. Maybe now is a good time to clean up your floating automatic pool chlorinator. Decontaminate them all at the same time.

Add the pool shock to the water gently. If you have to mix it in the bucket first, add water to the bucket and then add the shock to it. This avoids the spilling of water filled with chemicals.

  • Do not cover the swimming pool until the chlorine levels are back to normal.
  • Do not swim in the pool to check whether the chlorine levels are at 3 ppm or less.
  • Don’t try to save on the amount of shock. Do the math and use as much as required.
  • Drop this exercise if it is windy outside.
  • Brush your pool after shocking the pool so that the chlorine is evenly distributed.
no swimming sign


What is the fastest way to shock a pool?

The fastest way to shock a pool is to use a non-chlorine shock containing potassium peroxymonosulfate. This works in around 15 minutes.

How often should I shock my pool?

It is recommended to shock your pool at least once per week or after heavy usage or if the pH levels are off balance.

What are the benefits of shocking a pool?

Shocking a pool helps keep it clean and safe by killing bacteria and algae, removing odors, and increasing oxygen levels in the water.

What are the risks associated with shocking a pool?

The risks associated with shocking a pool include skin irritation, eye irritation, damage to outdoor plants near the pool, and potential corrosion of metal components in the pool area due to high chlorine levels.

Parting Words

Maintaining a clean, healthy swimming pool doesn’t have to be difficult or time-consuming. Properly shocking your pool will keep it looking great while also preventing algae overgrowth and other contaminants from entering the water.

Super chlorinating is an easy way to make sure your pool stays in perfect condition. Your swimming pool will not only look good and be healthy but it will also save you a lot more effort – if you skip the cleaning exercises.

Don’t wait till you start to see contaminants in your pool. That means they are at a point of such grossness that not only is it painful to look at but is unhealthy to dip a toe into.

Now you know how to shock a pool go get some practice! It really is a great way to keep your pool water in tip-top condition.

Last update on 2024-06-17 / Affiliate links / Images from Amazon Product Advertising API

michael keenan author

Author - Michael Keenan

I'm Michael Keenan the owner and creator of the Outdoor Care Guide. I'm a trained horticulturist with over 30 years of experience in pool care, plant care, and landscape care! Seemed like a good idea to share - I think I can make your life easier and save you some time and money!