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Pool Shock Buyers Guide

Not cleaning the pool for quite some time can turn it into a sea of algae floating around and making the pool unfit for use! Yes, there are a lot of pool cleaners available that promise to make your swimming pool spick and span, but that can take a lot of time, especially when you are craving to take a dip.

And that's why shocking a pool is essential. Using an excellent pool shock, you can exterminate the algae, and the strong chemicals make the pool ready to use.

When it comes to choosing the best pool shock, things can get stressful. There are multiple types of pool cleaners available that choosing the right type totally relies on the guesswork.

This pool shock buyer's guide promises you to make a quick and rewarding decision. We have explained all common types of pool shocks available in the market, so it'd be easier for you to choose.

What is a Pool Shock?

In simple words, a pool shock is a formulation of various chemicals that make your pool free from algae and other harmful chemicals, including bacteria.

When you add it to your pool, then it spikes the chlorine levels, thus boosting the amount of good chlorine required to kill the bacteria. The usage of pool shock depends on how frequently you want to use the pool and how dirty it is.

Factors to Consider While Buying a Pool Shock

Here are some essential factors you need to look for when buying pool shock. Checking these factors is important so that you can quickly choose the ideal type to clean your pool.

Furthermore, we have discussed the benefits you will get with each type to make things really straightforward for you.

Types of Pool Shock

Swimming pool shock is available in a variety of types with different features and cleaning power. You have to select the suitable type for your pool to attain the benefits it can offer by making the pool pristinely clean.

We have also talked about the pros and cons of each type.

Potassium MonoPersulfate

If you hate the smell of chlorine and need a chlorine-free pool shock, look for the options containing Potassium MonoPersulfate. Its effectiveness is not less than chlorine-based shocks, so you can rest assured that it will infest algae and contaminants to make the pool clean.

It works by oxidizing the water to boost the presence of free chlorine available in it. You won't be complaining about chlorine's pungent smell, so it is worth every single penny.

There's no chance that this pool shock will bleach the area around the pool liner, and that's another benefit of using this particular type. However, to attain these benefits, you have to pay more as compared to other options.

The fast-dissolving pool shock costs more, but it is a great deal if you just hate the presence of chlorine in the swimming pool.

Sodium Di-Chlor

Sodium Di-Chlor is a commonly used pool shock as it is cheaper than Potassium MonoPersulfate and gets your swimming pool ready within 15-390 minutes. The neutral pH level makes it friendly for your kin, and there will be no rashes or allergies if you take a dip in the water.

The reason why this type is known as Di-Chlor is the presence of chlorine. Chlorine is an essential component of pool shock that exterminates the bacteria, algae, and other contaminants making the pool clean.

Using Sodium Di-Chlor is easy, and you can simply put it inside the pool to see the cleaning action.

Calcium Hypochlorite

Calcium hypochlorite or cal hypo is the most affordable pool shock you can get. Available in 73% and 65%, it can clean the entire pool by infesting the algae and contaminants. For using cal hypo pool shock, you have to be extra careful as it cannot clean the pool in minutes.

The best time to put it into the pool is the evening when the UV rays cannot spike the chlorine breakdown. This is the strongest of all and can damage the pool liner by its bleaching action.

However, there are some downsides attached to using cal hypo, and that's an increased pH level. Further, the pool shock increases the levels of calcium in the pool, and it can take up to 8 hours for the levels to get back to normal.

A Pro Tip: While using cal hypo pool shock, consider neutralizing it by mixing it with water in a bucket. Also, it will help the mixture to dissolve faster and quick cleaning of the pool's water.

Which type of these is the best?

You can decide the best type of pool shock based on your requirements. If you want to infest algae, then cal hypo will be the best and most economical choice to get the job done.

On the other hand, if you want to clean and sanitize the swimming pool, then go with non-chlorine pool shock i.e., Potassium MonoPersulfate-based.

And if you need quick chlorine treatment, consider going with Sodium Di-Chlor, as it can get the pool ready as quickly as 15 minutes.

Liquid Vs. Powder

After choosing the right type of pool shock, it is time to select liquid or powder. Both options have their own pros and cons, and you can choose the suitable one based on your needs.

Liquid pool shock comes pre-dissolved, so you don't have to wait for the dissolving time. Also, it will not lead to bleaching the pool liner, and that's a significant benefit of using it.

Liquid shock is a bit more expensive as compared to powder, so you have to bear extra expenses for the convenience.

Powder swimming pool shock takes more time in dissolving, but once it dissolves fully, you can see its cleaning power. Powders are affordable, and you don't have to worry about any spilling issues in the storage cabinet.

Further, you have to be extra careful while using powder pool shock as it can bleach the pool liner.

Type of Swimming Pool

You can quickly select the best pool shock based on the type of pool you have. Using a suitable shock will ensure optimal cleaning without damaging the pool as the harsh chemicals can lead to bleaching the pool liner sometimes.

Now that you know about the different types of swimming pool shocks, it would be great to know about the suitable type depending on your pool.

Fiberglass Pools

Fiberglass pools are made using a durable layer or shell of fiberglass that's resistant to most of the chemicals present in pool shock, for example, chlorine. You can use any of these three types based on your budget and how quickly you want your pool to get cleaned.

Before adding the shock to the water, consider dissolving it in water, so it acts quickly, and you don't have to wait for a long time to get the swimming pool ready.

Vinyl Pools

PVC (polyvinyl chloride) or vinyl swimming pools are pretty common as these are available in both above-ground and in-ground options. You should avoid using highly chlorinated pool shock in these pools as the pH level can ramp-up quickly, which can bleach the pool liner.

Non-chlorine pool shock is the best option to safeguard your vinyl pool. Furthermore, non-chlorinated pool cleaners have quick cleaning action, so you don't have to wait for too long to plunge into the pool.

Concrete Pools

Concrete swimming pools have thick layers of concrete covered with a waterproof plaster. The plaster is highly resistant to bleaching or etching, so you won't face any issues if you use any of the three types of pool shocks.

Consider dissolving the pool shock if you are using powder-based to let it act quickly.

Size of the Pool

How bigger is the pool? Asking this question is important as it will help you decide the amount of pool shock you need. You cannot simply purchase pounds of chemicals as leaving the pool shock unused for sometime curtails its potency, and it will not clean the pool as it used to be.

A general thumb rule says you can use 1lb of pool shock for approximately 10,000 gallons of water. But it depends on several factors like how dirty the pool is and the cleaning power of the swimming pool shock.

The best way to determine it is by reading the instruction label of the pool shock. Most manufacturers clearly state it on the instruction label, so it becomes easy to decide the amount you need for the pool.

Lastly, consider how much time you will use the pool as you need more pool shock to keep it clean and free from algae and contaminants.

Dissolving Speed

The dissolving speed plays a significant role when choosing a swimming pool shock, as it would be helpful to avoid adding any un-dissolved granules to the pool. Most pool owners dissolve the granules in a bucket before pouring it into the swimming, and it is a highly suggested technique to use pool shock.

If you get a pool shock that takes hours to dissolve, then you have to sit back and wait for the dissolving process to complete. On the other hand, a pool shock that dissolves quickly allows you the assurance that you aren’t adding any un-dissolved chunks to the swimming pool.

Liquid pool shock has no issues related to the dissolution process, as you can simply add them to the water by measuring the quantity. If you want to get rid of the hassles of dissolving the pool shock, go with liquid options under your budget.

PH Level

Pool shock with neutral pH should always be your choice as higher and lower pH can harm the pool and users in many ways. If the pH level gets too high, then it can be harmful to the users. Irritation in the eyes, nose, throat, and mouth can be common problems you may face if the pH is not balanced.

Further, if the pH gets too low, the water can become highly corrosive, leading to damage to the metal pipes and other such things directly contacting the swimming pool water.

Going with neutral pH level pool shock will be the best deal as you can rest assured that the pool is safe for using and it won’t damage the pipes and other components in any way.

Chlorine Level

The purpose of a pool shock is to spike up the levels of chlorine (temporarily) sanitizing and cleaning the pool. But you should check the exact percentage of chlorine present in the mixture.

Some pool shocks like cal hypo have highly un-stabilized chlorine, which leads to bleaching the pool liner, and you cannot use the pool for hours until the chlorine levels come to normal.

You can go with non-chlorine pool shock if you don't want your pool to smell chlorine for hours. However, there are some excellent options available with less chlorine as well, so you can quickly get a good swimming pool shock.


Pool shock can have many chemicals present to improve its potency. From cal hypo to sodium di-chlor, every type of pool shock has some chemical additives present in it that make your pool clean while sanitizing it.

You should go for the options that have the least chemicals, so there are no hazards when you use the pool regularly. Using cal hypo can increase the amount of chlorine, whereas di-chlor increases the cyanuric acid in the water.

No pool shock is 100% free from additives, but a simpler option will be much better to avoid adding unnecessary chemicals to the swimming pool.


The price of pool shock varies depending on the type and consistency you choose. If you go for chlorine-free pool shock, you have to pay some extra bucks. Similar is the case with liquid shock, as it is expensive compared to granular pool shock.

You should avoid stocking up the swimming pool shock as it loses its potency with time. Get the only stick you will be using for the season to make sure that it serves you as promised.

FAQs about Best Pool Shock

Q: What’s the best time to use pool shock treatment?

A: Using the pool shock treatment at the right time will get you positive results and make the pool cleaner. If you use it during the afternoon or in the morning, then there are more chances that the blazing hot sun rays can curtail the effect of pool shock, and it can get dry inside the pool!

The heat emitted by the sun is like an enemy for the cal hypo pool shock because of the reduced chlorination. The best time to use it is after the sun gets down. Once you see that there's no direct sunlight on the swimming pool, it is the time to add pool shock, and the next morning you will get a clean pool free from algae and bacteria.

Q: How to use a pool chock correctly?

A: if you follow the proper techniques while using pool shock, excellent cleaning results are inevitable. Below mentioned is the correct process to use swimming pool shock.

  • Use the pool skimmer to get rid of the debris and leaves floating on the water. Also, pool shock can accumulate around the debris, so it is better to clean it beforehand.
  • To improve the potency of the pool shock, consider lowering the pH level to something around 7.2. You can use a pH calculator or litmus strips to reckon the current pH level.
  • Add the pool shock to the pool, and broadcast it among the entire surface and not just one specific spot.
  • Brush the pool to mix the swimming pool shock and let it sit for some time, depending on the type you have used.
  • If using cal hypo for vinyl pools, avoid sprinkling it on the pool liner to prevent bleaching it. You should clean any stains as soon as possible to prevent etching on the pool liner surface,
Q: Is there any substitute for pool shock?

A: If you want your pool to get free from algae and other such contaminants, then there is no better option than using pool shock. Using it is easy as a breeze, and all you have to do is add the mixture into the pool, and you are good to go.

Most pool shock products are affordable, especially if you go for cal hypo. So there's nothing to worry about.

Q: How long do I have to wait to use the pool after shocking it?

A: It depends on how dirty the pool is and what type of shocking treatment you have used. If using granular pool shock like cal hypo, then you have to wait for around 24-hours to use the pool as the chlorine levels may time to take a dip.

On the other hand, some chlorine-free pool shocks guarantee to make the pool ready to use within a few minutes. We recommend checking the pool's pH level before stepping in it so that there are no skin-related issues caused due to shocking the pool.

Q: Is there anything like over-shocking the swimming pool?

A: It won’t over-shock the swimming pool even if you add a little bit more amount of pool shock to the water. However, you have to be careful while using chlorine-based shock with vinyl pools. Using too much shocking treatment can damage the pool lines, and you have to avoid it.

Read the instruction label to determine the ideal amount you can add to the water for safe cleaning.

Q: Why is my pool looking green after adding pool shock?

A: The pool may look green due to the algae buildup on the water, and adding pool shock will help you infect the algae and bacteria. Wait for some time after you have shocked the pool, and the green color will clear, and the pool will be ready to use.

However, the excessive presence of copper in the water can also make it look a bit greenish after the algae clear.

Q: Is it okay to use a pool with algae?

A: Using the pool with algae isn't something you should do as it can be dangerous in many ways. Algae can cause various skin problems while mosquitoes can thrive on it, making things difficult for the residents.
Always shock the pool to clear the algae and then use it for swimming.

Q: How many times should I shock my pool?

A: It depends on how many times you want to use the pool and how quickly it gets dirty. Most pool owners shock their pools 1-2 times a week, and it's normal. Shocking a pool twice a week can help you maintain the chlorine level required to fight algae growth.

Q: How much pool shock do I need to clean 20,000 gallons of water?

A: The amount of pool shock you can use depends on various factors like the potency and type. On average, you can use 2lbs of pool shock for every 20,000 gallons of water. But we suggest you read the instruction label before shocking the water.


With this pool shock buyer's guide, you can select the best option for your swimming pool. Go through the different types and then choose the one that is suitable for your swimming pool. There's no substitute to shocking your pool, so it'd be great to get one today to make your swimming pool free from contaminants.

Also, check the FAQs to learn more about how to use pool shock and how you can prevent over-shocking the pool. Regular use of pool shock will help you maintain the pH levels so algae won’t thrive in the pool. / - © Copyright 2020