How to Shock Your Pool The Easy Way

There are many ways to keep your swimming pool water clean and perfectly balanced. But you want to find something that is safe and tried and tested. Super chlorinating, also known as shocking, is one such technique.

I’ll show you how to shock your pool and explain everything you need to know in plain and simple terms. Shocking a pool is super easy and really effective!

This is a weekly or bi-weekly process where you add a lot more chlorine than usual and shock the pool for a short time to kill the bacteria and any other nasties!.

how to shock a pool

Types of Pool Shock

There are several chemical sanitizers that you can use to shock your pool.

Calcium hypochlorite is the cheapest one but it does not last as long as the others if the pool is in sunlight. It is strong and dissolves quickly so apply it at night. It is available in the form of granules. So, you must dissolve it before you add it to the pool.

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Sodium dichlor is another option which gives a longer-lasting shock. This is also available in the 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.

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Or you could get lithium hypochlorite. This is good if you have high levels of calcium in the pool because it does not. Check for the calcium levels of your pool using a test kit. This one is the most expensive types of chlorine.

Typically, you must wait eight hours after adding any of these chlorine mixes. But you can pick a non-chlorine product if you want to be done with it and get to swimming in about 15 minutes. These products have potassium peroxymonosulfate and it does not kill algae.

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Why This 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’s 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. 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.

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Step 1: Fill up the test tube by dipping it to 1.5 feet 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 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!

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.

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.

Parting Words

A clean pool is an absolute joy. It should come as no surprise that that takes some amount of maintenance. If you do this once a week or in two weeks, you will be able to get exactly that result.

Your swimming pool will not only look good and be healthy but it will also save you a lot more effort that you need to put in if you skip the cleaning exercises. The best way to do that is to get to the bacteria and algae when they are still at an invisible point.

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 deathly 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.

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 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!