Everything you need to know about pool shock

Pool shock

Everything you need to know about pool shock

If you’re looking to stay on top of your pool maintenance and avoid expensive servicing bills then you should add pool shock to the list of chemicals you regularly use. In this article, we explain everything there is to know about pool shock. If you’re looking to buy some affordable and effective granular pool shock then we sell that, too. In short, keep reading this article and you’ll find out everything there is to know.

What is pool shock?

In short, pool shock is like superpowered chlorine. It’s the pool chemical you use after your pool has experienced heavy use or perhaps that have been large amounts of rain. When you shock your pool, you drastically raise chlorine levels in order to kill off germs and bacteria through a process called “super chlorination”. In doing so, you kill off what’s known as “chloramines”. The term is used to describe the combination of chlorine disinfectants with oils, sweat and even urine in your pool.

Types of pool shock

There are several different types of pool chemicals available on the market, and knowing the difference between each is important prior to making a purchase. The main types are as follows:

  • Calcium hypochlorite
  • Lithium hypochlorite
  • Sodium dichloride
  • Non-chlorine pool shock

Calcium hypochlorite

Manufactured in granular form, calcium hypochlorite is one of the most widely available shock sold throughout pool stores.

This is because it is the cheapest and strongest form of pool shock available. The downside is that it’s best to use at night, due to the adverse effect the sun has on the chemical.

Lithium hypochlorite

If your pool has high levels of calcium in it then you will want to use lithium hypochlorite pool shock, as it contains no calcium

Also, you can add this directly to your pool without the need to dissolve it in a bucket of water, as is the case with calcium hypochlorite pool shock.

Sodium dichloride

Like calcium hypochlorite, sodium chlorine comes in granular form. The difference is that this is a slow-dissolving pool shock. Therefore, it kills germs for longer.

When you use sodium dichloride, you need to pay attention to your pool’s cyanuric acid levels, as these will tend to rise.


Also known as potassium peroxymonosulfate, this kind of pool shock is commonly used among pool owners with vinyl liner pools.

As the name suggest, this shock is not chlorine-based. It is actually oxygen-based and oxidizes in the pool water, boosting chlorine levels.

The upside of non-chlorine pool shock is that you may jump in your pool relatively soon after applying the pool shock.

How to shock your pool?

Shocking your pool is a quick and easy process. In fact, you can do it in five easy steps. Here’s the short version first:

  1. Use protective gear
  2. Prepare the chemicals
  3. Shock your pool & let it rest
  4. Check your chemical balance
  5. Run your filters

If you’re after a more detailed explanation though then continue reading.

Step 1: Use protective gear

As many chemicals can hard your skin or ruin your clothes, it’s important to protect yourself. Therefore, make sure you use protective gloves, enclosed shoes and protective eyewear.

Step 2: Prepare the chemicals

If you choose to go with granular shock i.e. Pool Magic Aqua Shock then you will need to prepare the chemical by diluting it in a 20L bucket of water.

What you shouldn’t do is poor the shock directly into your pool. Doing so could end up damaging your equipment, including the filter and pumps.

If you use pool shock such as lithium hypochlorite though, then pouring it directly into your pool is ok. In any case, make sure that you read the manufacturer instructions.

Step 3: Shock your pool & let it rest

As we sell granular pool shock, we recommend that you dilute it in a bucket of water first. Then, pour it evenly around the edges of your pool.

You need to let the shock do its work, so leave it for about 24 hours prior to continuing to the next step.

Step 4: Check your chemical balance

Once you’ve left your pool overnight, the next step is to check your chemical balance. Make sure you do this before you let anyone jump in for a swim.

Your pH levels should be between 7.2 and 7.6 – this is really important. If your pH level is too high, for example, then shocking it will be useless.

Step 5: Run your filters

Pool shock will do a great job of killing off germs in your pool, but it won’t carry them out. For that, you need your filters.

Run you pool filter for about 24 hours after you have shocked your pool.

FAQ’s about shocking a pool

Now that you know how to shock your pool, here are some answers to some common questions that pool owners have.

How often & when should you shock your pool?

We recommend that you do this between once and twice per week during the swimming season, depending on how often you use your pool.

In terms of when you should shock your pool, we recommend doing so before during the following times:

  • Before opening your pool for summer
  • Before closing your pool for winter
  • After heavy rainfall or extreme weather conditions
  • After heavy use
  • After the first sight of algae

Additionally, the best time to shock you pool is definitely at night. Sunlight will decrease the effectiveness of pool chlorine, and the same applies for pool shock.

Also, shocking your pool at night means you’re more likely to leave it for longer, allowing your pool shock to work for longer.

How long does the process take?

In terms of shocking the pool – from preparing the chemicals to pouring it in – the entire process shouldn’t take any longer than one hour.

How long until you can jump in your pool?

Following that, you may not be able to use your pool for a minimum of 8 hours. This is because you need to make sure that chlorine levels are settled by checking your chemical balance.

Additional tips

Here are some additional and helpful tips when it comes to effectively shocking your pool

  • Never, ever add your pool shock directly to the skimmer
  • Make sure your pool remains uncovered until chlorine levels return to normal
  • Don’t let anyone jump in until you’re absolutely sure that chlorine levels are at 3ppm or less
  • Brushing your pool after pouring in the shock chemicals will help distribute it more evenly

Affordable and effective pool shock at factory direct prices

Save when you buy your flocculant at Pool Magic Pool Care. Our products are factory direct, meaning we offer some of the cheapest pool chemicals to our customers. Call or email us to order today.

Pool Magic Aqua Shock (Low Residue Calhypo)

Granular non-stabilised shock treatment

Minimum available chlorine is 700g/Kg present as Calcium Hypochlorite
Package for use as shock treatment
Low residue

Kills & controls algae & bacteria
No affect on stabiliser levels
Convenient single dose pack sizes for shock dosing, includes unique measuring cap for easy application

4 times daily dosage for stabilised pools
(Daily dosage is 35g per 10,000L per day for stabilised pools)
Twice daily dosage for non-stabilised pools
(Daily dosage is 70g per 10,000L per day for non-stabilised pools)
Dissolve granules in water prior to use or add directly to water
Dosage rates indicated are only a guide – refer to directions for use

Pack Sizes Available:
2Kg (6 units/carton) & 10Kg

SKU: PMS002 Category:

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