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Anyone who has the necessary basic knowledge and has already carried out shock chlorination several times will quickly become proficient in the correct procedure.

Reading Tip: Pool maintenance guide

Pool shock chlorination is important to neutralize algae, bacteria, chloramines, insects (such as mosquito larvae in the pool) and other foreign matter in the pool. Only in this way can the typical pool odor be prevented and the water remains hygienically clean.

What is pool shocker and how does it work?

Many people confuse the familiar “pool smell” with chlorine odor. In fact, free chlorine pool hardly smells. The penetrating swimming pool odor is due to substances called chloramine.

The fact that the pool smells at all is not the result of the use of chlorine, but a sign of insufficiently maintained pool water.

Chloramines are formed as a by-product of the reaction of chlorine ions with foreign organisms. The disinfectant chlorine binds to other particles to neutralize them, becoming combined chlorine.

Chloramines are not only the cause of the chemical odor, but can also cause skin, respiratory and eye irritation. Pool shocker consists of (free) chlorine and other chemicals.

These are added to the water to destroy the molecular structure of chloramines, bacteria, pathogens and other foreign bodies.

The structure of the chloramines can only be attacked if at least ten times the amount of free chlorine is present in the pool water.

The free chlorine is the portion of the active substance that really disinfects and keeps the pool clean. If the amount of free chlorine during shock chlorination is not sufficient, the chloramine will not dissolve either.

When must shock chlorination be performed?

Perform shock chlorination at least every two weeks. In some cases, the next shock chlorination should be brought forward. This serves the purpose of keeping the pool clean, odorless and safe for health. Special circumstances include:

  • great change of the water level
  • Wild animals bathed in the pool
  • heavy pool use (e.g. because of a pool party)
  • high temperatures in summer
  • heavy rainfall, during which visible deposits have formed in the pool

In the summer months, the load on the pool is higher (and also because more people swim in it). Therefore, from June to August, the swimming pool should be treated weekly with pool shocker.

A pool shock chloren (step by step guide)

With the theory in mind, we now go into practice. Shock chlorinating a pool is not witchcraft. In fact, with this step-by-step guide and our tips, it’s shockingly easy.

Most pool shockers contain non-stabilized chlorine, which is quickly banished by the sun. Therefore, shock chlorination may only be performed at night.

The pool water should also not be heated or cooled. The ideal water temperature for shock chlorination is 15 to 18 °C and the optimum pH value is 7.2.

Step #1: Choose the right material

Before shock chlorination can begin, you need to gather some equipment and a few pool chemicals. When dealing with pool shockers, it is important to exercise caution. For this reason, put on protective gear and wear older clothes where stains would not be a problem.

Checklist: What you need for shock chlorination

  • Test kit or test strips
  • Protective gloves
  • Safety goggles
  • old pants and old long sleeve shirt
  • sturdy, closed shoes
  • Pool shocker
  • Wooden stick
  • 20 liter bucket

Step #2: Test pool water

Subsequently, the pool water must be examined. The measured values are the basis for the dosage of the pool shocker. Use a test kit with tablets or a test strip for pool water testing.

Most test strips and kits cover the most important values. For shock chlorination of the swimming pool, the chlorine concentration with the total chlorine (TC) and free chlorine (FC) as well as the pH value are of particular interest.

Reading Tip: Test pool water

Step #3: Correct pH (if necessary)

In regular operation, the pH value should be between 7.2 and 7.6. A too high pH value (alkaline pool water) would be particularly problematic for shock chlorination, as the effect of chlorine is inhibited in alkaline pool water. If the pH in the pool is too low or the pH in the pool is too high, it must be corrected.

If the pH is too high, you should apply pH-Minus before shock chlorination. This pool chemical can be used to lower the pH. Follow the manufacturer’s instructions for use and dosage.

Step #4: Calculate shock chlorination

You don’t have to be a math genius to calculate the dosage of the pool shocker. Simply calculate the amount of pool shocker step by step:

  1. Find the concentration of combined chlorine (CC). To do this, simply subtract the free chlorine (FC) content from the total chlorine (TC).
  2. Multiply the value CC by ten.
  3. From this product subtract the concentration of free chlorine (FC).
  4. Check the pool shocker packaging or the manufacturer’s website to see how many grams of pool shocker are needed to cause a 1 ppm change in free chlorine in 10,000 liters.
  5. Divide the volume of your swimming pool by 10,000.
  6. Multiply the pool volume (step 5) with the amount of pool shocker for a change of 1 ppm (step 4) and the missing free chlorine (step 3).
  7. You can now divide the result of the last step by 1,000 to obtain an indication in kilograms. This amount of pool shocker must now be put into the swimming pool.

Step #5: Add pool shocker to water

Once the correct dosage has been calculated, it is time to add the pool shocker to the water. Be careful handling the chemical and always put on protective gloves.

The packaging of the pool shocker or the manufacturer’s website will explain how to use the particular product.

Some manufacturers recommend dissolving the pool shocker first. To do this, fill a 20 liter bucket about 3/4 full with warm tap water.

Then add the pool shocker to the water in increments of 500 grams at a time, stirring the solution slowly with a wooden stick to allow the pool chemical to dissolve.

The best way to pour the dissolved pool shocker into the water is to walk slowly around the pool while pouring. In this way, the agent is well distributed in the pool.

The same is true for pool shockers in tablet form. Distribute the tablets evenly in the swimming pool.

Step #6: Run filter system

Turn on the filter system so that the chlorine is completely distributed in the pool and filter system. Shock chlorination is performed in the evening. Just leave the pool pump running overnight.

After shock chlorination, the pool water may be milky or cloudy the next morning.

Either wait a few hours for the turbidity to subside or use water clarifiers to make the swimming pool crystal clear again immediately.

At least eight hours must elapse between treatment with pool shocker and the first swim. By then, the excess free chlorine will have dissipated. The short forced break must be to avoid skin and eye irritation.

FAQ

What is pool shock chlorination?

Surge chlorination is the short-term overdosing of chlorine. The process is used in swimming pools or similar pools to combat algae infestation or other contamination or to protect freshly filled water from contamination. Here, the chlorine content is increased to 10 mg/l. Learn more.

How often should a pool shock chlorination be performed?

Generally, it is recommended to perform a pool shock chlorination every two weeks. In summer, the load on the pool is higher, so weekly pool shock chlorination is more effective. Learn more.

How do I properly perform a pool shock chlorination?

Pool shock chlorination sounds more complicated at first than it actually is. To do this, put on your protective clothing, calculate the amount of chlorine needed, dissolve the pool shocker, add pool shocker to the water and wait. Step-by-step instructions.

When can I go swimming again after a pool shock chlorination?

After pool shock chlorination, it takes about 8 hours to get back into the pool. However, this is only a guide value. You should not swim in the pool again until the chlorine level is below 3ppm (parts per million). Learn more.

How much chlorine does my pool need?

For a private pool, the chlorine content is 0.5 to 1.0 mg per liter. At higher temperatures, the chlorine content should be increased to 0.7 to 1.2 mg/l. Learn more.

Conclusion

Shock chlorination of the pool is part of a pool owner’s regular duties. Even if routine quickly sets in, you must always exercise caution. When handling pool shockers, wearing protective clothing is mandatory.

Store pool shockers in a cool, dry and dark place. Never mix different types of pool shockers. Also, do not breathe in the air that flows out of the storage container when it is opened.

You should also purchase a respirator for chlorinating larger pools. With the small amounts of chlorine required for a private swimming pool, a mask is not necessarily needed.

After reading this, you’ll be almost a real expert when it comes to shock chloren. With our tips and this step-by-step guide, pool shock chlorination will be a breeze, but your own safety must always be considered.

The editorship of Wellenliebe.de consists of real water sports fans. From kayakers, sailors and divers to stand up paddlers, (almost) all water sports are represented. Our content has been read millions of times and has been picked up in many newspapers.

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