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The 13 Best Pool Shock for Crystal Clear Water


Owning a swimming pool requires you to take care of a wide range of maintenance and upkeep if you want to keep it at its best.

If you’re new to pools, you may not have encountered a pool shock before, so what is this stuff and why should you care?

Well, shocking your pool normally involved delivering a high dose of chlorine that serves to kill bacteria and algae, while at the same time clarifying the water in your pool. Pool shock ensures that your water looks great and stays safe and clear, too.

The process of shocking increases normal chlorine levels by up to 5 times, fully sanitizing the water in the process. During the process, pool shock also oxidizes combined chlorine molecules, which leads to a boost in the free chlorine levels. Free chlorine is “good” chlorine, in that it will target algae and bacteria.

Given the fact you may never have seen pool shock before, it’s understandable if you have no clue what you’re looking for when you’re comparing the best pool shock treatments. Focus on the following points to make your life easier on the buying trail.

  • Stabilized or unstabilized shock: Pool shock containing sodium dichlor is termed stabilized pool shock. With this variety, the chlorine remains protected from the sun, and will not suffer from UV-ray damage. With unstabilized shock, you need to apply it at night. During the day, this type of pool shock dissipates too quickly
  • Chlorine level: Most pool shocks contain chlorine, and the concentration of this active ingredient is instrumental to its efficiency. The higher the percentage of chlorine, the more effective the pool shock. Use too little chlorine and the shocking will be ineffectual, use too much and you could create more problems with other chemical levels going out of kilter
  • Powdered or liquid pool shock: The majority of pool shocks come in powdered form. This is easy to use and simply needs pre-mixing. Liquid pool shock works well if you want to prevent your liner becoming bleached by chemicals. This typically costs more in exchange for that convenience
  • pH neutral: Look for a pool shock that won’t impact the pH levels of the water in your pool. When pH levels are too low, the water becomes corrosive and this will ruin the piping and any metal components in your pool. With pH levels too high, the acidic water will irritate your eyes, mouth, and nose
  • Minimal ingredients: When you’re shocking the water in your pool, you want it to impact the water as little as possible outside of your intended purpose of oxidizing it. Look for solutions containing as few ingredients as possible. Calcium hypo will, unsurprisingly, raise the calcium levels in your water. Dichlor adds cyanuric acid to the water. While it’s tough to find pool shocks that are additive-free, look for formulas with as few added extras as possible
  • Speed of results: Not all pool shock is created equally. Some solutions promise results nearly instantaneously while others take up to 24 hours. This is certainly not the most crucial element of your buying decision, but it’s worth bearing in mind when you’re shopping pool shocks

OK, with those basics in place, you should be confident of navigating the best pool shocks on the market and finding the right one for your needs.

We’ll launch in now with our pool shock reviews so you can assess the state of the market.

The 13 Best Pool Shock

1. Our Pick: In The Swim Chlorine Pool Shock



  • 68% calcium hypochlorite
  • 1 pound per 10,000 gallons
  • 12 x 1 pound

First up and overall favorite in our collection of the best pool shock comes a formula heavily laden with calcium hypochlorite.

Pre-portioned into small bags containing just the right amount of shock for each pool treatment.

This shock works well for regular maintenance, and the concentration of chemicals means it’s also highly effective if your pool requires a rapid chlorine boost.

If you have an especially cloudy or dirty pool, the high levels of chlorine will rapidly kill then dissolve all bacteria and algae.

The conditions of your swimming pool will dictate how often it needs shock treatment. As a guideline, you should apply this crystalline shock once weekly.

For vinyl pool owners, this shock doesn’t make a good fit, so we would recommend exploring some of the other shocks on our shortlist. For most other types of swimming pool, you’re getting one of the best and most potent chlorine shocks out there, and it’s quite keenly priced, too.

As crowning glory, this is a highly reputable brand in this space, so you can buy with complete confidence and the knowledge you’ll soon be improving the quality of the water in your pool.

Things We Like Things We Dislike
  • No need for measuring
  • High levels of calcium hypochlorite
  • Great overall value
  • Doesn’t work with vinyl pools

2. Best Non-Chlorine Shock: In The Swim Chlorine-Free Pool Shock



  • Potassium monopersulfate
  • 1 pound per 10,000 gallons
  • 12 x 1 pound

If you sanitize your pool every week, you may want to consider supplementing that regime with a chlorine-free pool shock. Another offering from In The Swim, you’re buying into great brand heritage here.

This is a powerful oxidizing shock that can help you achieve higher free chlorine levels in your pool while also eliminating chloramines from the water.

The composition of the formula allows you to use it with just about any sanitized pool.

It’s the main ingredient – potassium monopersulfate – that gets to work reactivating any inactive chlorine in your pool. By doing this, and also eliminating the non-sanitizing chlorine, your pool water should stay crisp, clear, and algae-free.

Dissolving in just 15 minutes, this is also a fast-acting shock perfect for anyone always crunched for time but not prepared to sacrifice pool health.

We would like to see a higher concentration of the active ingredient in this formula, but we feel that you’re getting great value overall, and one of the most effective non-chlorine pool shocks you can find.

Things We Like Things We Dislike
  • Doesn’t impact other chemical levels
  • Works with all pool types
  • Dissolves in 15 minutes
  • Low amount of active ingredient

3. SpaGuard Enhanced Shock



  • 2% sodium dichlor
  • 15-minute dissolve time
  • 2 pounds

This enhanced shock from SpaGuard makes a great choice if you have a spa or hot tub and you want to keep the water looking spotless.

This multipurpose shock serves the following 4 functions:

  • Shocks
  • Clarifies
  • pH buffer
  • Flocculent

While the listing suggests that this shock works well in tubs and spas with either chlorine or bromine, we would recommend only using this stuff with chlorine-based systems. We found some complaints from consumers with bromine-based systems reporting that this shock turned the water green.

Containing 58.2% sodium dichlor, it takes around 15 minutes before you notice the effects of this shock.

This bundle contains just a single 2-pound bottle of shock, but you can also opt for several different multipacks if you are looking for even greater value.

In addition to keeping the water in your spa or hot tub sparkling clean, you will also appreciate the way this treatment eliminates any nasty odors that might otherwise build up in your tub.

While this might not be the cheapest pool shock out there, it’s one of the finest examples if you are lucky enough to have a pool or hot tub in your back yard at home. If you act quickly, you can pick up this enhanced shock at a slight discount, too.

Things We Like Things We Dislike
  • Multiple configurations to suit
  • Ideal for spas and hot tubs
  • Super-simple to use
  • Only suitable for chlorine systems

4. HTH Ultimate Shock Treatment



  • 56% calcium hypochlorite
  • 1 bag per 13,5000 gallons
  • 6 x 1 pound

If you have a swimming pool at home, you are likely aware of HTH, an industry heavyweight with a deep bench of pool products including this highly versatile shock.

Of all the treatments we review today, this is arguably the most comprehensive option at your disposal.

Firstly, this treatment will increase the chlorine levels in your pool. This serves both to kill bacteria and also to keep algae at bay, both key for proper pool hygiene. All you need to do is test the chlorine levels in your pool weekly, ideally between 1pm and 4pm for best results.

Compatibility is comprehensive. Whether you have a gunite pool, an above-ground pool with a liner, or a saltwater system, this versatile pool shock makes a smooth fit. If your pool has a vinyl liner, you won’t need to worry about this stuff fading the vinyl over time either.

This stuff turns blue to show you that it’s getting to work, and you should notice the quality of the water in your swimming pool improve in as little as 24 hours.

A single 2-pound of this shock is enough for the treatment of 13,5000 gallons of water. This bundle gives you 6 of these bags, so you may need to dig deep, but you’ll be getting more than enough shock for a few months of use.

Things We Like Things We Dislike
  • 7-in-1 shock treatment
  • Clearer pool water in 24 hours
  • Helps prevent algae from forming
  • Pretty pricey

5. SpaGuard Enhanced Pool Shock



  • 58% sodium dichlor
  • 1 pound per 10,000 gallons
  • 6 pounds

If you have a spa or a small swimming pool at home, you’ll find the water can end up easily contaminated with body oils, cosmetics, and perspiration. These compounds can easily irritate your eyes and your skin. By shocking or oxidizing the water, you can remove these compounds along with any algae or bacteria.

This is a multi-purpose shock that delivers 4 distinct benefits:

  • Clarifier
  • Shock
  • pH buffer
  • Flocculent

You’ll be able to put this stuff to work quickly, too. Treating the pool should eat up no more than 10 or 15 minutes.

By adding this solution to your spa water, you’ll return it to the shining brilliance you see in the ads rather than the murky reality of an untreated pool. This stuff is compatible with both chlorinate and brominated spas. It also works with either ionization or ozone systems.

The active ingredient in this formula is sodium dichlor at a concentration of 58%. We like the transparency of the ingredients listing, something that’s not always the case with pool shock.

As a non-stabilized shock, you should only use this treatment at night. During the day, you’ll find it dissipates too quickly.

For home spas, this is flat-out one of the best pool shocks you can find. See what you feel.

Things We Like Things We Dislike
  • Restores water sparkle
  • 4-in-1 functionality
  • Removes bad smells
  • Non-stabilized

6. hth Super Shock Treatment



  • 56% calcium hypochlorite
  • 1 pound per 10,000 gallons
  • 12 x 1 pound

When you’re comparing the best pool shocks, you’ll encounter the brand hth repeatedly. They have a heavy presence in this vertical with just cause: they make some of the best pool shock out there.

Containing 56% of the active ingredient calcium hypochlorite, you can expect to notice visible results in as little as 24 hours. This elevates the shock above much of the competition in this regard.

While efficiently clarifying your pool water, this treatment won’t overstabilize the pool either.

If you’re a longstanding customer of the hth brand, you should be aware that the company has overhauled the packaging. So, you’ll be getting the same great formula in a slightly different look, but the same impressive results.

Although the granules dissolve pretty quickly, we would like to see them dissolve more fully.

You get 6 x 1 pound packs of this pool shock, so you won’t need to fuss around measuring this stuff out. Dump the pre-portioned amount into your swimming pool and let the efficient formula get right to work. There are other bundles available if you want smaller quantities of shock.

Eliminate skin and eye irritation and start enjoying your pool without any discomfort this summer with this outstanding pool shock from hth.

Things We Like Things We Dislike
  • Fast-acting and dissolving
  • Reduces eye irritation
  • Doesn’t overstabilize pool
  • Could dissolve more effectively

7. Clorox Pool and Spa Shock



  • 58% sodium dichlor, 37% available chlorine
  • 15-minute dissolve time
  • 6 x 1 pound

Next up in our collection of the best pool shocks comes a classic formula from the highly reputable Clorox. You may recognise this brand from products you use in the kitchen or bathroom, and you’ll get the same super-efficient chemicals here for your swimming pool.

The multi-functional pool shock does more than most in this market segment. You’ll enjoy the most glimmering and clear water after treating it with this solution, and any algae will also be killed stone dead. This solution can decimate green and black algae, as well as mustard pool algae. You’ll also see off any rogue bacteria polluting the pool water.

The formula contains a high concentration of sodium dichlor (58%). It’s an ideal treatment if you need to open up a swimming pool that’s become contaminated during the off-season. Throw some of this stuff in and you’ll be ready to dive in 15 minutes later.

Unlike some less effective pool shocks, you won’t experience your pool’s pH levels being thrown out of kilter.

With the exception of woefully poor instructions, this pool shock represents an outstanding investment if you want to restore an unused pool to its former glory in next to no time.

Things We Like Things We Dislike
  • Kills all types of algae
  • Multifunctional shock
  • Doesn’t affect pH levels
  • Instructions are unclear

8. Zappit Hypo Pool Shock



  • 73% calcium hypochlorite
  • 1 pound per 40,000 gallons
  • 50 pounds

Next up in our selection of the best pool shocks, Zappit delivers a hard-hitting calcium hypo formula that’s well worth a place on your shortlist.

Coming in a supersized 50-pound drum, you’ll need 1 pound of this treatment to deliver 2ppm of AC (available chlorine) across a pool with a capacity of 40,000 gallons.

The granular formula is easy to ladle into your pool, and once in the water, it dissolves quickly and gets to work instantly.

This is a powerful shock treatment that’s tailor-made for reinvigorating the water in your swimming pool this spring so you can enjoy a lengthy swimming seasons with no contaminants in your pool water.

You’ll need to make sure you are at home for delivery of this shock treatment. A signature is required due to the nature of the product.

In sum, this is a fast-acting and efficient pool shock perfect for opening up your swimming pool this year.

Things We Like Things We Dislike
  • Granules dissolve quickly
  • 70% available chlorine
  • Clarifies water
  • Signature needed on delivery

9. hth Super Pool Shock



  • 56% calcium hypochlorite
  • 1 pound per 13,500 gallons
  • 12 x 1 pound

Next up comes another entry from the inimitable hth. This is another formula containing a high concentration of calcium hypochlorite at 56%.

One of the key draws with this formula is the fact it works in just about any swimming pool, giving you complete freedom. You won’t find this stuff fading your vinyl pool, and it also make a smooth fit with saltwater systems.

By boosting the overall chlorine level, you will experience a superior water clarity in your pool, and you’ll also ensure there is no bacteria or algae to ruin the effect while compromising your health.

This bundle comes with 12 packs of 1-pound bags, each ideal for a single pool treatment. Look to shock your pool weekly for optimum results. Each of the bags contains enough of the formula to shock a 13,500-gallon pool.

You can expect to notice results and an improvement in water clarity within as little as 24 hours after shock treatment. A few disgruntled users point out that the water initially turns cloudy, but this will soon normalize, and your pool will be sparkling when you next dive in.

Things We Like Things We Dislike
  • Works with all pools
  • Ideal with saltwater systems
  • Great overall value
  • Initial haze to water

10. DryTec Chlorinating Shock Treatment



  • 68% calcium hypochlorite
  • 1 pound per 10,000 gallons
  • 24 x 1 pound

As we near the end of our pool shock reviews, DryTec serves up a great value pack of 24 x 1-pound bags of pool shock. Each of these will shock a pool to 10,000 gallons.

This treatment is manufactured by a compressed air filter specialist in business for decades producing highly efficient solutions like this pool shock.

Like with many pool shocks, you may notice some sediment when you first add this stuff to your pool water. This is normal and will soon disappear.

Containing 68% calcium hypochlorite, this is one of the most concentrated solutions on the market.

You should ideally apply this shock in the evening while your pool filter is running. Use the entire contents of a pre-portioned bag. Use a brush to disperse any of the treatment that doesn’t dissolve.

As with all pool shocks, you’ll also need to make sure that you regularly test your pool. Take care of this and you’ll benefit from crystal clear pool water like you’d expect at the country club without needing to leave home or lift a finger.

Things We Like Things We Dislike
  • High levels of calcium hypochlorite
  • Destroys organic compounds
  • Quick to act and dissolve
  • Some sediment initially

11. Clorox Pool & Spa Shock Plus



  • 72% sodium-based dehydrant
  • 15-minute dissolve time
  • 12 x 1 pound

Clorox is a household name in the swimming pool vertical, with a wide range of accessories like this pool and spa shock.

You get a bumper pack containing 12 bottles of 1-pound pool shock. This should see you most of the way through the swimming season, depending on how often you choose to shock your pool water.

The key benefit of this treatment is the way it clarifies your pool water, making it much more appetizing to dive into.

Ideal for all vinyl pools, this shock gets right to work without fading your liner over time.

As an inbuilt kicker, the 4-in-1 formula restores clarity in your pool water without impacting the pH levels in your pool – what’s not to love?

Using this stuff couldn’t be easier thanks to the bottles provided. It is worth pointing out that a handful of consumers complain about receiving plastic packets of shock in place of the advertised bottles. Do your due diligence here. Having said that, almost all user reviews of this shock are positive.

If you treat the pool at the right time of the afternoon, you could be swimming in as little as 15 minutes, so what are you waiting for?

Things We Like Things We Dislike
  • Bottles are easy to pour
  • Multipurpose formula
  • Will not affect pool pH
  • Some quality control concerns

12. Doheny’s Chlorine Super Shock



  • 68% calcium hypochlorite
  • 1 pound per 10,000 gallons
  • 24 x 1 pound

For any pool owner looking for a weekly treatment that will shock the water and ensure it’s crystal clear, the ever-reliable Doheny’s hit a home run as expected.

Containing 68% calcium hypochlorite, this is highly concentrated shock that gets the job done quickly.

You get a great value pack here with 24 bags each containing 1 pound of shock.

By oxidizing your pool water, you’ll burn of the spent chlorine cells – chloramines – which enables the new chlorine you’ve introduced to work at maximum capacity.

If you’re looking for clear pool water without the expense of hiring a pool maintenance crew and without any physical effort, Doheny’s pool shock is a must.

Things We Like Things We Dislike
  • Available in bulk
  • High levels of chlorine
  • Highly reputable brand
  • Questionable customer service

13. Aqua Chem Pool Shock



  • 68% Calcium hypochlorite
  • 1 pound per 10,000 gallons
  • 5 x 1 pound

To complete our selection of the best pool shocks, we have a great offering from Aqua Chem with this Shock Extra Blue, named for the difference this treatment can make to the quality of your pool water.

The manufacturer recommends using this formula once weekly for best results.

You get a 5-pack of 1-pound bags, so you won’t need to worry about dosing. Applying this shock couldn’t be easier, but what does it do once it’s in the pool water?

Well, you’ll eliminate any bacteria and algae, removing any threat to your safety. You should experience no irritation to your eyes or your skin once you’ve treated the water with Shock Extra Blue.

Now, although this shock won’t disrupt the pH levels in your pool, we encountered a few complaints from users about the copper content of the formula impacting other pool levels. You’ll need to do your own due diligence here.

For sparkling pool water the easy way with a formula from a brand you can rely on, Aqua Chem Shock Extra Blue represents outstanding overall value while delivering unbeatable performance. You can buy huge bumper packs containing up to 36 packs of treatment if you’re looking to optimize value further.

Things We Like Things We Dislike
  • Doesn’t increase pH levels
  • Kills algae and bacteria
  • Makes water sparkle
  • Copper content can throw other levels out


By now, you should have a clear understanding of the various types of pool shock you can find, as well as how each type stands and falls.

We’ve reviewed all the best pool shock so you can readily compare them and determine which, if any, makes the best fit for your home swimming pool. If you don’t find anything that you like here, we hope our handy buying guidance informs your decision and allows you to easily pick the best shock for your needs.

Before you head off today, take a moment to bookmark Wild River Country. We’re here to cater for all your home swimming pool needs by guiding you through finding the best swimming pool gear the easy way. Come back soon!

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