What is pool shock?

Pool shock is a process of adding chemicals to kill all organic substance causing diseases, infections and algae formation. The most common pool chemical used to shock a swimming pool is chlorine because it is inexpensive and effective.

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Why shock your pool?

It is necessary to shock your swimming pool simply because it kills the bacteria and other organics on a molecular level, thus, neutralizing and oxidizing these harmful contaminants, which makes your pool germ-free and safe.

When to shock your pool?

You can shock your pool whenever it needs it. Pool professionals suggest that you shock your pool a minimum of once per month. Although, it is still best to shock your swimming pool once a week or more frequently.  Conditions like heavy rain, storms, hot temperatures, or using your pool heavily indicates a need for frequent shocking.

However, the best indicator is the chlorine level.  As guidelines for normal chlorine values, the recommended free chlorine level is 0.5-1.5 ppm, 0-0.5 ppm for combined chlorine level and 0.5-1.5 ppm for total chlorine level. If the chlorine level is below the recommended levels, then it is time to shock your pool.

You should also add chlorine at the right time. It is best to shock your pool during the night. The chlorine works better when added during the night because there is no UV light coming from the sun. UV light affects the chlorine, making it weak and less effective.

Which pool shock to use?

Pool shocks come in granular and liquid forms; however, professionals use granular pool shock more often than liquid form. Granular pool shock contains 47% chlorine and is available in concentrations up to 75%, while liquid pool shock contains only 10% chlorine and 90% salt water. Swimming Pool Maintenance

How to shock your pool?

Shocking your pool takes a lot of hard work and expertise, which is best left for professionals to do. However, for you to have an idea on how to do it, below are the steps on How to Shock Your Pool the Easy Way.

  1. Perform a water chemistry test by taking a sample of the pool water. A specific amount of water is necessary for accurate readings.
  2. Determine the water’s free chlorine level and total chlorine level. If both readings are the same, then there is no combined chlorine level. However, if the total chlorine level is more than the free chlorine level, this indicates your combined chlorine level.
  3. Calculate the amount of free chlorine needed. For every 1 ppm worth of combined chlorine, you must add 10 ppm of chlorine to remove it.
  4. Add chlorine to the swimming pool according to your calculation.

It is important to ask pool experts for help to determine the proper ratio of chlorine to pool water to achieve proper treatment. Pool Doctor of the Palm Beaches offers pool shock treatment and other pool products and services. You can contact them at (561) 203-0270 or browse their website at You can also subscribe to their Pool Podcast on iTunes and via RSS.