What Is Total Residual Chlorine?
Chlorine is most commonly used in swimming pools and is measured in different forms. Some types of chlorine values that are often measured are combined chlorine and free residual chlorine.
Testing these values of chlorine is very important when it comes to swimmers’ safety and health.
Sources of Total Residual Chlorine
Total Residual Chlorine is tested and found in pool water and drinking water — in much lower amounts in drinking water. The same tests kits used to test swimming pool water can test drinking water chlorine levels.
Chlorine levels in drinking water taken from the tap and stored in containers lessen over time, while swimming pool water with chlorinators that disperse regularly usually increase levels, which is why testing needs to be done often.
Types of Chlorine
Free chlorine residual level is a measurement of the residual chlorine as chlorine gas, hypochlorous acid and hypochlorite ions released in the water. Combined chlorine consists of bacteria and chlorine that builds up as chlorine kills contaminants.
The waste produced is called chloramine. Total Residual Chlorine is often measured in swimming pool water.
What is Total Residual Chlorine?
Total residual chlorine is free residual and combined residual chlorine measurements, combined. It is sometimes abbreviated as TRC.Total residual chlorine measurements should not exceed 3.5 ppm (parts per million) in pool water.
Chlorine testing of swimming pools should be done at least twice a week.
Tests for Total Residual Chlorine
There are several ways to test total residual chlorine. The most common used testing method is liquid reagent test kits, in which you collect water, pour in a chemical solution and look for a change in color.
Another testing method is the color wheel. These are similar to the liquid reagent kits, but come in tablet or powder form and also rely on color changes to determine results. The most reliable method is similar to the other two, water is poured into a vial, liquid or tablet chemicals are added, except a meter is used to read the results.