Final answer:
To address high chlorine levels in a secondary tank, one should dilute the chlorine concentration by adding more water. Maintaining correct chlorine levels is essential for water safety, as both insufficient and excessive chlorine can pose health risks.
Step-by-step explanation:
If the results from a secondary tank chlorine test are too high, the action that should be taken is a) Dilute the chlorine concentration. High levels of chlorine can be harmful, and therefore, it's essential to adjust the concentration to safe levels. One can dilute the chlorine by adding more water to the system, effectively reducing the concentration of chlorine. The other options such as adding more chlorine, taking no action, or stopping chlorine treatment immediately are not appropriate responses to high chlorine levels.
Chlorine helps to eliminate bacteria and other biological contaminants in water, so maintaining correct levels is crucial for water safety. However, excessive chlorine can cause adverse health effects and must be managed carefully. Methods for determining chlorine demand involve adding incremental amounts of chlorine to water samples and establishing a balance where any substances that can be oxidized by chlorine are fully reacted while retaining the desired chlorine residual.