What is Pool Shock

Pool shock refers to using a powdered form of chlorine, which is commonly referred to as granular oxidizer.

Why might you have to perform pool shock? The pool shock process works to remove combined chlorine molecules, which you commonly referred to as a Chloramine. 

More so, pool shocking occurs to help remove excessive bather waster and bacteria levels, especially if it's a high traffic pool. Plus, the process also works to help remove visible algae and contamination events that might occur. Bromine treated pools and spas also implement pool shock techniques to help restore bromide ions' functionality.

There are three main reasons as to why you may have to perform a pool shock process:

  • Algae – green, pink, black, or yellow, the best way to exterminate such a problem would be to raise the Free Chlorine level (10-30ppm). Why? Because it will help to oxidize or exterminate these contaminants. You can control the development of pool algae by using some algaecide. That said, to exterminate algae and clean the pool, the best solution would be pool shock. Ensure that you adjust the pH range to between 7.1 – 7.3. Making such an adjustment ensures the chlorine is potent. Killing algae blooms will require, on average, between 10-30ppm. Also, chlorine accelerators such as Yellow Out are ideal for promoting chlorine levels to exterminate algae blooms. 

  • Bacteria and bather waste – bacteria can also get to the pool through several sources, with most of them being relatively harmless. That said, pathogenic bacteria are also common. Use chlorine shock techniques to help eliminate bacteria after excessive use, long winters, heavy storms, etc. Plus, bather waste includes products such as cosmetics, soaps, hair, lotions, and more. 

  • Chloramines, contaminants, and cloudy water should know that combined chlorine molecules are responsible for the "red-eye" side effect and strong chlorine smell. The solution at this point would be to ensure chlorine levels don't surpass the 0.5 ppm-level. If this is the issue, then add some chlorine and non-chlorine shock. These products will work well to regulate the amount of combined chlorine in your swimming pool.

The Important Facts When Using Pool Shock

the important facts when using pool shock

Pool shock is a process pool owners, and contractors use to eliminate contaminants from swimming pools. There are lots of harmless matter that will get to your pool, and compromise the balance of water. You can correct cloud water with super chlorinating techniques, or by adding chlorine oxidizer. These are chemicals that ensure you can destroy colloidal particles that can lead to cloudy water. 

Put merely, chlorine shock works best for exterminating algae and bacteria. On the other hand, non-chlorine shock offers the best Chloramine and Contaminant removal results. Below are some of the common points in time you should expect to use pool shock:

  • Startup and close down – for pools that are winterized, opening the pool will be the first time when you use pool shock when the water chemistry level is correct. Using it at such a point ensures it oxidizes the particles, exterminates bacteria, and algae – perfect for restoring the water's clarity. Before you decide to shut down the pool for the season, consider using pool shock to make things convenient for the upcoming season. 

  • Heavy rain – rain is pure water, which undergoes distillation through evaporation. That said, it may pick up airborne particles as it falls through the air to your pool. Many issues might compromise water quality. These include dust, pollen particles, algae spores, and more. More so, during heavy rain, overhanging trees, large plants, or yard spaces that are close by might also compromise the water quality. 

  • Chloramines – free chlorine converts to combined chlorine when it mixes with ammonia or nitrogen. The bond causes the chlorine molecule to become useless, causes a strong smell of chlorine, and irritates swimmers' eyes. Using DPD tests, kits will be beneficial for determining Free and Total chlorine. You may have to use pool shock to remove chloramines when the levels surpass 0.3 ppm. 

  • Other applications – for pools that have several users, or pools that are contaminated with urine, vomit, or feces, shocking is the best solution in cases where the chlorine levels depleted, due to issues such as hot temperature, faulty equipment – using pool shock can be an excellent solution.

How Frequent Do You Need to Shock A Pool? 

Each pool is unique, and there are various factors to consider before performing pool shock. It's a process that works to remove bacteria, chloramines, and various types of contaminants. Also, pool shock is a process that helps remove cloudy water or various other water complications. The presence of algae should be a strong sign of pool shock effectiveness. That said, pathogens and other bacteria are not visible to the human eye. Thus, many pool owners recommend shocking pools after 3-4 weeks, even if the water is clear and clean.

Chlorine vs. Non-Chlorine Pool Shock

When using any of these products, it's good to follow the instructions on the package. Usually, it will provide useful information on the length of time to wait after shocking, before getting into the pool. Using large amounts of granular chlorine needs a large timespan (24-48hrs) before the pool is safe enough to use (5ppm). Before using the pool, ensure you determine the nature of the product used for the best results.

Even more, chlorine-free shock treatments contain potassium and various salts. More so, it also offers various other benefits that you would not necessarily get with chlorine-based pool shock techniques. 

These products' strengths vary in relation to brands, but most non-chlorine products contain 37% - 42.6% Potassium Monopersulfate, aka MPS.

Non-chlorine Shock Pros

  • Quick-release, potent, no odor and residue

  • No pre-dissolving required and you just pour into the pool

  • Eliminates ammonia and toxic products

  • Won't fade or bleach items such as swimsuits or vinyl liners

  • You can use them immediately with no waiting times

  • Does not add cyanuric acid or calcium to the pool

Non-Chlorine Shock Cons

  • Not as powerful for algae and bacteria treatment

Chlorine Shock Treatments

These are available in two common types – the Dichlor and Cal Hypo. Using calcium hypochlorite is the most popular, potent, and cheapest solution for pool shock. Usually, the two categories of these treatments include the Shock and Super Shock. Plus, Dichlor consists of stabilized granular pool shock, which is produced by the stabilizing compound. Such a technique ensures the product is safe from direct sunlight or exposure to moisture.

Chlorine Shock Pros

  • Fast-acting and quick release

  • Removes ammonia and chloramines

  • Eliminates bacteria and algae fast

  • Cheapest method for shocking the pool (Cal Hypo)

Chlorine Shock Cons

  • Pre-dissolving granular is ideal for protecting the surface

  • Waiting for 24 hours is recommended

  • High levels of chlorine can be harsh on some surfaces

Estimating Pool Shock Amount

How much pool shock should you use? You may first have to determine the amount of water in your pool. If you are not sure, take some measurements, and consult a local swimming pool contractor. Usually, the dosage amount of pool shock averages at 1 lb. Per 10,000 gallons. That said, ensure you check the labeling of the package before using the product. The dosage amount recommended for a specific pool depends on the severity of the contamination.

When it comes to removing chloramines, shock the pool until it reaches the Free Chloramine level. Usually, this amount ranges between 10-20 times the amount of measured chloramines used in the pool shock process.

For the removal of chloramine, shock the pool until it achieves a Free Chlorine level, and it should be 10 to 20 times the amount of measured chloramines. To remove algae, 30ppm is usually accepted, but you can also use more or less. Plus, it also depends on the severity of the algae bloom. 

You can use various resources to calculate the amount of pool shock you need to treat your pool. Plus, if you still notice the watercolor is still green, then this shows the water is compromised with algae. Thus, you might have to use more of the product. Check with your product labeling or a local contractor on the specific chlorine amount levels to use.

Pool Shock Longevity

What is the longevity of pool shock? Storing pool shock products in the cold and dry places is crucial in maintaining their potency. Additionally, storing the product in a garage or store can easily compromise its quality. Thus, storage is vital if you want to keep granular products in storage. 

Remember that plastic bags are also prone to damage. Thus, for the ideal storage results, it would be good to use Cal Hypo Buckets. Ensure the lids are tightly sealed to keep out moisture accumulation.


Taking good care of your pool is an essential factor to consider. Why? If you want to avoid dirty water and health complications, it's best to make an informed decision for your pool each time. Thus, this is why we have discussed the topic," what is pool shock." It's simply a process that you use to clear your contaminants pool that might lead to health issues.

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