Chlorine Pool Shock: When, Why and How

Shock chlorine, also known as rapid chlorine, restores optimal disinfection of your pool in a minimal amount of time. It will also be very useful at the opening of the season or when the pool turns green. Here is everything you need to know about this.

Why Is It Called "Shock" Chlorine?

In granular form, it has high chlorine content and high water solubility. It is the solubility of the product that gives it its name shock chlorine, or fast chlorine since its action is much faster than slow chlorine where dilution speed is lower.

Two Types of Shock Chlorine

• Stabilized (dichloroisocyanurate): which contains a stabilizer (isocyanuric acid), that prevents chlorine deterioration by UV light.;
• Unstabilized (calcium hypochloryte): much more unstable, it should be handled with care. It does not contain a stabilizer, so it is much more sensitive to the effects of the sun.

Chlorine Shock Treatment, When and Why?

Fast chlorine is to be used in addition to a basic treatment with slow chlorine tabs. It is advised to be used as a remedial treatment:

• In the spring, after the winterization of your pool. Accompanied by thorough manual cleaning and continuous filtration.;
• When the water in your pool becomes cloudy and the disinfection capacity of your water (ORP) is too low, do a shock treatment to quickly restore the situation.;
• During hot weather, algae can grow in your pool, shock chlorination can solve this problem.;
• After heavy use of the pool, to avoid any imbalance or bacteria growth.;
• After outdoor pollution (storms, heavy rain, wildfires, etc.), a shock treatment can be considered in order to quickly restore the swimming water to its correct condition.

We have a dedicated article if you need more information.

User Guide

• Measure and balance the pH of your pool before performing a shock treatment. A pH that is too high will considerably reduce the effect of the chlorine. So make sure your pH is between 7 and 7.4.
• Start continuous filtration.
• Calculate the quantity of product needed in relation to the dimensions of your pool. Usually, suppliers recommend adding 200g of stabilized fast chlorine per 10m3 of water. If you have the iopool application, simply follow the exact recommendations of the product to be added.
• Dilute the shock powder in a bucket of warm water before spreading the mixture in your pool. This way, you will prevent the powder from settling on the bottom of the pool and ensure optimal diffusion.
• Wait at least 1 to 2 hours before swimming.

The iopool Shimmer N' Shock

iopool offers very high quality, stabilized shock chlorine (99.7% active ingredient) in its range of cleaning products. You can order right here.