What is the primary setting for a Hach colorimeter used in water testing?

The primary setting for a Hach colorimeter used in water testing is the low range (LR). This setting is specifically designed to accurately measure low concentrations of various substances commonly found in water samples. Many water quality tests focus on detecting trace amounts of contaminants, nutrients, or other chemical parameters, which makes the low range setting particularly important for ensuring that tests can effectively identify and quantify these substances.

The low range capability allows for sensitive detection that is crucial in various applications, such as monitoring drinking water quality, assessing the health of aquatic ecosystems, and ensuring regulatory compliance. Tools like the Hach colorimeter are calibrated to provide precise measurements that can detect low-level concentrations, which is essential for identifying issues that may not be visible to the naked eye.

Alternative settings such as high range or medium range may be applicable in other scenarios or for different types of samples, but they are not primarily used for testing low concentrations in water, which is why the low range is the most relevant for this context.