What instrument is primarily used to test for total chlorine in water treatment?

The Hach pocket colorimeter is the primary instrument used to test for total chlorine in water treatment. This device employs colorimetric analysis, which involves the addition of specific reagents to a water sample. When these reagents react with chlorine in the sample, they produce a color change, the intensity of which correlates with the concentration of total chlorine present.

The colorimeter is specifically designed to measure this change accurately, allowing for precise determination of chlorine levels. Total chlorine tests are critical in water treatment processes to ensure that disinfection is effective while avoiding harmful levels of chlorine and its byproducts.

While other options are useful in various water quality assessments, they are not suited specifically for measuring total chlorine. A pH meter measures acidity or alkalinity, a conductivity meter assesses the water's ability to conduct electricity (related to ion concentration but not chlorine specifically), and a water quality analyzer typically measures multiple parameters but would not specialize in total chlorine without specific configurations or additional methods. The Hach pocket colorimeter's specificity and ease of use make it the preferred choice for determining total chlorine concentrations in water treatment.