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What Is an Active Chlorine Bleach Test Strip? How Do I Use It?

Active Chlorine Bleach Test Strips are designed to test the level of either free chlorine or both free chlorine and total chlorine in a solution. Active Chlorine Bleach Test Strips are also known as Chlorine Test Strips or Active Chlorine Test Strips. This test kit is conveniently easy to use.

Free Chlorine vs. Combined Chlorine

When chlorine is added to water, some of the chlorine reacts first with inorganic and organic materials and metals in the water and is not available for disinfection. After the chlorine demand is met, the remaining chlorine is called total chlorine. Total Chlorine consists of combined chlorine and free chlorine.

  • Free Chlorine - is the chlorine that is left over and is available to inactivate disease-causing organisms; it is a measure of the potability of the water

  • Combined chlorine - is the amount of chlorine that has reacted with inorganic (nitrates, etc.) and organic nitrogen-containing molecules (urea, etc.) to make weak disinfectants that are unavailable for disinfection.

The goal of dosage testing is to determine how much chlorine to add to water that will be used for drinking to maintain free chlorine in the water for the average time of storage of water in the household (typically 4-24 hours). This goal differs from the goal of infrastructure-based (piped) water treatment systems, whose aim is effective disinfection at the endpoints (i.e., water taps) of the system: defined by the WHO (1993) as: "a residual concentration of free chlorine of greater than or equal to 0.5 mg/L (0.5 ppm or parts per million) after at least 30 minutes contact time at pH less than 8.0." This definition is only appropriate when users drink water directly from the flowing tap. A free chlorine level of 0.5 mg/L of free chlorine will be enough residual to maintain the quality of water through the distribution network, but is most likely not adequate to maintain the quality of the water when this water is stored in the home in a bucket or jerry can for 24 hours.

Safe Amount of Chlorine in Drinking Water

Drinking water should have an optimal concentration of chlorine between 0.3PPM and 0.5 PPM Levels from 0.22 PPM - 4 PPM are still acceptable. Ingesting water with chlorine levels above 4 PPM can cause negative health effects. At the same time, chlorine in water isn't considered dangerous until it reaches above 4PPM water with 2 PPM chlorine tastes and smells like chemicals.

Steps on how to use Active Chlorine Bleach Test Strips

  • Get the needed strips from the container and close immediately. Use the strips as soon as possible.

  • Dip strips into the mixture sample for 2 seconds

  • Wait for 10-15 seconds and compare the resulting color of the test pad to the printed color chart on the label

Things to avoid when doing the test

  • Do not dip test strips in the mixture for more than 5 seconds

  • Do not wet printed color charts

  • Always store bottle in a dry place away from direct sunlight


As part of the US Regulation, chlorine added to any solution need to be tested and should be within the required chlorination. Thus, the easy and accurate way to do it is through the chlorine test strips. Always read instructions provided by the manufacturer to avoid inaccurate results.





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