The 9 Best Pool Shocks

Updated December 20, 2017 by Brett Dvoretz

9 Best Pool Shocks
Best High-End
Best Mid-Range
Best Inexpensive
Pool shocks are a superior alternative to mere chlorine when you have mucky water. They'll eliminate algae and bacteria while maintaining your water's pH balance without as much of an offensive chlorine odor. Keep your pool sparkling with something from our selection. They also work well as a treatment deployed at the beginning and end of swimming season. When users buy our independently chosen editorial picks, we may earn commissions to support our work. Skip to the best pool shock on Amazon.

9. Clorox Plus

The Clorox Plus is packaged in convenient bottles that make treating a breeze. Just twist off the lid, pour in what you need, and close the container until next time. As an added benefit, it won't affect the pH levels of your water.
  • contains blue algae killing crystals
  • application instructions included
  • sometimes requires multiple uses
Brand CLOROX Pool&Spa
Model 32012CLX
Weight 15.2 pounds
Rating 4.1 / 5.0

8. HTH Super

The HTH Super removes chloramines and organic waste, which cause eye irritation and strong odors, by adding free available chlorine to the water. If you'd like to stock up for the season, it also comes in a value priced 30-pack box.
  • buffered for ph control
  • targets harmful bacteria
  • takes up to 48 hours to clear pool
Brand HTH
Model 51424
Weight 5.4 pounds
Rating 3.9 / 5.0

7. Kem-Tek Super Quick

With the Kem-Tek Super Quick you are free to start swimming just 15 minutes after application, giving it a leg-up on other brands. A single bag in this 10-pack box can kill the algae and bacteria in as much as 20,000 gallons of water.
  • removes stains from plaster walls
  • replaces other cleaning chemicals
  • best if added on weekly basis
Brand Kem-Tek
Model 26449048231
Weight 9.4 pounds
Rating 4.0 / 5.0

6. BioGuard Burnout3

BioGuard Burnout3 is a high-powered formula that is specifically designed to be used on any type of pool without damage, even if you have a vinyl liner. It is also compatible with bromine sanitizers, and doesn't need to be pre-dissolved like similar products.
  • dose is 1 pound per 10000 gallons
  • destroys organic contaminants
  • must circulate water when added
Brand BioGuard
Model BIO22808
Weight 12.5 pounds
Rating 4.0 / 5.0

5. DryTec Chlorinating Treatment

DryTec Chlorinating Treatment is an extra-strength start-up and maintenance option that improves the appearance of your water by removing and preventing algae growth. It provides a fast acting chlorine boost using 68% calcium hypochlorite.
  • restores crystal clarity
  • controls cyanuric acid levels
  • has a very strong smell
Brand DryTec
Model 1-1901-24
Weight 26.5 pounds
Rating 4.4 / 5.0

4. Aqua Chem Xtra Blue

Aqua Chem Xtra Blue is ideal for periodic treatments when you need to get water back in shape after letting it go for a while. It does an excellent job of killing bacteria and algae, and doesn't cost a fortune, particularly when purchased in one of the several bulk packs.
  • suitable for all wall materials
  • just walk around the edge and pour
  • ready to swim after 15 minutes
Brand Aqua Chem
Model 12101AQU
Weight 5.5 pounds
Rating 4.4 / 5.0

2. Pool Essentials Treatment

Situated at the intersection of quality and value is the Pool Essentials Treatment. This budget priced option can be applied through the skimmer or put directly into the deep end, where it will start to work within a few minutes.
  • apply any time of year
  • only need to apply once per week
  • reduces chlorine odor
Brand Pool Essentials
Model 25556ESS
Weight 6.5 pounds
Rating 4.6 / 5.0

1. Doheny's Super Bag

Doheny's Super Bag features calcium-hypochlorite as the active ingredient to help clear even the most contaminated water, and each bag has a two- to three-year shelf life, so they can be stored in your shed through the winter without compromising effectiveness.
  • ok to use in salt or fresh water
  • one bag treats up to 10000 gallons
  • no measuring required
Brand Doheny's
Model 7701
Weight pending
Rating 5.0 / 5.0

What Is Pool Shock And Why Is It Needed

Pool shock is a concentrated chemical that can either be chlorine or non-chlorine based. It is used to increase free chlorine levels in your pool thereby decreasing combined chlorine. Combined chlorine or inactive chlorine is responsible for the skin irritation, red-eye and chlorine smell that people experience in some swimming pools. It is formed when the available chlorine you add to your pool in the form of sanitizer combines with organic compounds after it breaks them down and kills them. Once it has combined with the dead organic matter, it becomes inactive and is known as chloramine. The only way to remove combined chlorine is by adding excess free chlorine, which breaks apart the chloramine molecules and oxidizes it.

Without proper swimming pool sanitation, pools would quickly become filled with harmful bacteria that could cause swimmers to become sick. In addition to regularly adding chlorine or another sanitizer, pools must be shocked periodically to keep them clean and safe for swimming. The more often a pool is used, the more often it must be shocked. This is because the majority of the organic matter that renders free chlorine inactive comes from bathers. It can be in the form of sunscreen, dead skin cells, and sweat. Additional organic matter comes from leaves and dirt that enters your pool from the environment.

Adding pool shock gives your regularly used sanitizer a boost when levels are running low. Shocking a pool is also a great way to help establish correct levels of free chlorine in a newly filled swimming pool or one that is being readied for the summer after winter time neglect.

Types Of Pool Shock

Pool shocks can be chlorine or non-chlorine-based. Chlorine-based pool shocks include calcium hypochlorite, commonly referred to as Cal-Hypo, Lithium Hypochlorite, and dichloroisocyanuric acid, more commonly referred to as Di-Chlor. Non-chlorine-based pool shock is made from potassium monopersulfate.

Cal-Hypo is the most commonly used pool shock in home pools and is also the most powerful in terms of oxidation. Its main ingredient is calcium hypochlorite, and it is available in different concentrations, usually in the 65% to 75% range. There are also Cal-Hypo pool shocks advertised as allowing you to begin swimming within 15 minutes after use. This is because these products typically contain just 47% calcium hypchlorite, which may be enough to allow swimming without irritation, but is often not enough to effectively destroy all bacteria and chloramine molecules. Cal-Hypo will add both calcium and chlorine to your pool, so if your calcium hardiness is already high, it might be best to consider another shock option.

Lithium hypochlorite pool shocks are one of the best options, but are often overlooked by pool owners because of their higher cost. It is a completely soluble fine granular that dissolves instantly in water. Instead of incorporating a calcium filler like Hypo-Cal, it utilizes lithium. The standard formula contains 29% lithium hypochlorite and 35% free chlorine. It can be used in all pool types, including those with vinyl liners, leaves no binder residues, and allows you to begin swimming immediately after use.

Di-Chlor also dissolves rapidly and can safely be used in vinyl-lined pools. It is less costly than lithium hypochlorite, but more costly than Hypo-Cal. Instead of calcium or lithium, it makes use of cyanuric acid. The use of cynauric acid is a double-edged sword. On one hand, it prevents chlorine from quickly dissipating in direct sunlight, but over time excessive use can cause a buildup which limits chlorine's effectiveness.

Potassium monopersulfate non-chlorine pool shocks are not as powerful as chlorine-based products, but they are a good alternative to those worried about the harmful effects of excessive chlorine use. Instead of adding additional chlorine to a pool, potassium monopersulfate oxidizes the organic matter so the current chlorine in your pool can do its job more effectively. They also help remove cloudiness from a pool's water. Potassium monopersulfate pool shocks are pH neutral, calcium-free, and allow you to swim immediately after use.

How To Shock A Pool

When shocking a pool, it is important that you take the necessary safety precautions to avoid injuring yourself or damaging your pool. Wear safety gloves to protect your hands and glasses to protect your eyes.

The first step is to fill a five gallon bucket with water. Always add pool shock to water, never the other way around. If you add the pool shock to the bucket first, you run the risk of it splashing onto you as you fill the bucket with water. Stir the pool shock around the bucket and agitate the water to dissolve the shock granules. Once it is completely dissolved, you can begin adding the mixture to your pool water.

With the filter running, slowly pour the shock and water mixture into your pool water directly in front of the pump's return line fitting. This will help to circulate the shock around the pool and ensure that it doesn't settle onto the bottom. Never pour it directly into the skimmer.

When you have about 25% of the shock and water mixture left in the bucket, stop pouring it into the pool and add more water to top of the bucket. This will help dissolve any shock granules which did not fully dissolve the first time. If you see any granules settling on your pool floor, take out your pool brush and sweep them around to help them dissolve. If left on the pool floor they can damage it and cause bleaching.

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Last updated on December 20, 2017 by Brett Dvoretz

A wandering writer who spends as much time on the road as behind the computer screen, Brett can either be found hacking furiously away at the keyboard or perhaps enjoying a whiskey and coke on some exotic beach, sometimes both simultaneously, usually with a four-legged companion by his side. He hopes to one day become a modern day renaissance man.

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