Pool Sanitizer vs Shock: Choose the Best Cleaning Option?

Robert Wimberly

pool sanitizer vs shock

Diving into the sparkling blue waters of your pool is one of life’s simple pleasures. However, maintaining that water clarity and purity isn’t always as straightforward as you might think. It can feel like you’re stuck in a pool of choices with the best cleaning solutions.

Sanitizers and shock serve a similar goal in sanitizing your wading pool. However, they’re used for slightly different purposes. Thus, knowing these differences between pool sanitizer vs shock is paramount to maintaining pristine and bacteria-free water.

So, dive in with us as we compare these two primary arms of your pool cleaning arsenal. We’ll ensure those pool days are as safe and enjoyable as possible!

Here’s a table that summarizes the disparities between pool shock vs sanitizer:

Sanitizer Shock
Chlorine concentration Less potent Highly-concentrated
Main purpose Kills harmful microorganisms, algae, and viruses Kills bacteria and pathogens

Treats algae outbreak

Removes chloramine from water

Need for other compounds Not needed Requires chlorine to boost cleaning
Frequency Daily to weekly Every one or two weeks
Impact on water clarity May cause cloudiness Clears cloudy water
Toxicity Low High

What is a Pool Sanitizer?


Do you want to keep your pool water clean and germ-free? If yes, you need pool sanitizers!

As their name suggests, these chemicals are efficient in killing bacteria, viruses, and other contaminants lurking in your pool water. In other words, they sanitize the water to create a safe and hygienic swimming environment.

Pool sanitizers have been used for water disinfection and purification for centuries. They mainly contain sodium hypochlorite and some forms of hypochlorous acid. In addition, these sanitizers have oxidation properties that make your pool water crystal clear.

There are several types of pool sanitizers available in the market. They are:

  • Liquid Chlorine: Liquid chlorine is the convenient choice for many pool owners as it doesn’t need dissolving and comes in refillable containers. Aside from this type (which is often used weekly), you will come across tablet and granular chlorine.
  • Tablet Chlorine: This variation, like the granular form, suits daily application. It also dissolves gradually and has a longer shelf life than liquid chlorine.
  • Granular Chlorine: Takes the most effort to use out of the three forms, as you need to ensure the powder doesn’t sit and remain clumpy at the bottom of the pool.

Pros & Cons

  • Purges all germs
  • Easier to use
  • Non-toxic
  • Cheaper yet effective
  • Not very potent in treating algae outbreak

What is Pool Shock?


You might be surprised to learn that a pool shock is a concentrated version of pool sanitizers. It is formulated to raise chlorine levels by 5 ppm in a few hours, and is often used to restore balance when a pool has become overwhelmed by contaminants.

For example, you may apply shock after a rainstorm or a party.

Even if you’re sanitizing regularly, occasional pool shocking provides the necessary impetus to kill harmful bacteria and algae. It also burns off chloramines that cause an unpleasant smell, eye irritation, and cloudy water.

There are three basic types of shock treatments for pools. They are:

  • Calcium hypochlorite (cal hypo): It is a super-concentrated granular chlorine that releases oxygen and chlorine to eradicate contaminants swiftly. It’s vulnerable to UV-related degradation, however, and must be used in the evening.
  • Sodium Dichlor (dichlor): This substance combines chlorine and cyanuric acid for efficient shocking and is fine to use in daylight without problems.
  • Potassium monopersulfate (PMS): A non-chlorine formula, PMS isn’t the best cleaning solution. However, it is perfect for removing odors and improving the efficacy of your chlorine.

Pros & Cons

  • Super potent for pool sanitation
  • One-time application
  • Clears cloudy pools
  • Activates free chlorine
  • Wait for at least a day before using the pool.

Which is Better: Pool Sanitizer or Shock?

Are you confused about whether to use shock instead of chlorine? Consider the following factors to determine the best cleaning product for your wading haven:

1. Potency and effectiveness


As discussed, the primary difference between chlorine and shock is their strength. If you prefer potency, opt for the latter. Nevertheless, the former is best for consistent disinfection and cleaning if your pool has no severe issues.

2. Duration


Both are capable products for pool sanitation. But when it comes to how long they take to use, sanitizers will have the upper hand as they require only a few hours of your time.

Unless you opt for the non-chlorinated version, which works within fifteen minutes, pool shocks will prevent you from swimming for an entire day due to their highly corrosive characteristic.

3. Safety


Generally, sanitizers are safer if you can follow basic instructions. Pool shocks require careful handling to avoid irritations or injuries.

Also, no one should swim until the shock treatment has fully circulated and chlorine levels have dropped to the recommended 1-3 ppm level.

4. Budget


When it comes to the cost of pool shock vs. chlorine, the latter may incur consistent expenses. Shocks are less regular because you only need them when the water is very dirty.

But to give you a ballpark, chlorine costs $3 to $5 for a gallon of liquid. 20 pounds of tablets will retail for $100 at the cheapest, and granular chlorine can set consumers back $6 per pound.

In comparison, a pool shock’s cost is about $50 to $150, depending on how large your swimming space is.

A Quick Guide to Using Pool Sanitizer and Shock Safely


The following scenarios also help you identify the best time to use pool shock instead of sanitizers:

  • Massive growth of green, black, yellow, or pink algae
  • Presence of chloramines
  • Cloudy pool water
  • After heavy storms and rainfall
  • Before and after winter (start-up and closing down)

Guide to using pool sanitizer and shock safely:

  • Strictly follow the manufacturer’s safety guidelines. You cannot shock the pool with chlorine tablets as they’re not strong enough.
  • Choose and dispense the correct quantities.
  • Wear protection gear like gloves or goggles.
  • Do not dip the same tool or equipment in multiple types of products.
  • Never mix different types of chemicals.
  • Keep children and pets away from pool chemicals.
  • Properly dispose of empty containers.


Pool sanitizers and shocks differ in strength and application yet aren’t rivals. Instead, they’re allies in creating a clean, safe, and enjoyable swimming environment. That said, the choice between pool sanitizer vs shock need not come as an either-or decision.

As pool owners, we recommend understanding how they work best in conjunction to remove stubborn contamination, clear cloudiness, and restore the sparkling cleanliness of your water. Enjoy your well-maintained, picture-perfect swimming pool!

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