Which testing method is regarded as a backup for measuring total chlorine?

The method identified as a backup for measuring total chlorine is the use of RPC ultra low total chlorine strips. These strips are specifically designed for the accurate detection of low levels of chlorine in water, making them particularly useful in situations where alternative methods may not provide reliable results or need confirmation.

Using these strips can be particularly advantageous because they are portable, easy to use, and provide quick results, which is essential for monitoring water quality in various settings. In contrast, a colorimeter may be the primary method employed for measuring total chlorine due to its accuracy and ability to quantify chloramine levels; however, it can be less practical in field situations.

A pH meter is not suitable for total chlorine measurement as its primary function is to measure the acidity or alkalinity of a solution. Similarly, a conductivity meter measures the ionic content of water, which does not directly correlate to chlorine levels. Thus, the utility and functionality of ultra low total chlorine strips make them a reliable backup option for total chlorine measurement.