Superchlorination, also known as shocking or chlorine shocking, is the process of adding several times more chlorine to the pool than is normally needed so that the chlorine can "burn" through resistant compounds, chemicals, oils and strong types of algae. Usually adding chlorine to reach a level of 10 parts per million (ppm).

Always Superchlorinate with the filter on, and do so weekly during the swimming season to clear a pool of any excessive contaminants. You should always do it with the filter pump turned on, not off. There are two reasons for this; Firstly, the filter needs to be working in order to catch any dead bacteria or dead algae that the Superchlorination has killed. With the filter system off, these particles would just float to the surface or even stay where they are. Secondly, the pump system needs to be working to spread the chlorine throughout the pool area evenly, or it will not have the same effect.

Use different methods of Superchlorination, depending on the type of pool and how dirty it is. Superchlorination generally requires three to four times the regular dose of chlorine, although milder Superchlorination methods are available that only raise the chlorine to 3 ppm. Either way, know the normal amount of chlorine your pool is expected to have, and have enough chlorine to shock the system above that mark. With enough chlorine, even the tough compounds that have bonded to the original chlorine particles will be dissolved.

Your pool may also have a Superchlorination option for its filtration and chlorination system that you can switch to. This mode will automatically increase chlorine flow to shock levels and then decrease it as needed. Make sure you have enough chlorine in your pool system for Superchlorination before you turn on this setting.


The high levels of chlorine used when Superchlorinating pools can make them dangerous to swim in, so always make the pool or spa off limits while you Superchlorinate it. Superchlorination will only last about a day after adding the chemicals.

To be sure, you should always test the pool after Superchlorination. Safe chlorine levels are around 1 to 2 parts per million.

If you're not sure whether you should superchlorinate your pool see the article titled "What is superchlorination" in our Pool FAQ's section or talk to your local Swimart pool and spa specialist.

TIP: Superchlorination at regular intervals is a big part of keeping your water clear, clean and safe for use.