What does it mean to "backwash" a filter?

Backwashing a filter involves reversing the flow of water through the filter media in order to clean it. This process is essential for maintaining the efficiency and effectiveness of the filtration system in a pool. Over time, debris such as dirt, leaves, and other materials can accumulate in the filter, causing it to lose its ability to properly filter the water.

When backwashing, the flow of water is directed in the opposite direction, allowing the trapped debris to be flushed out of the filter and sent to the waste line. This not only cleans the filter but also helps to restore proper water flow and pressure within the filtration system, ensuring that the pool water remains clear and free of contaminants.

The other options do not accurately describe the backwashing process. Replacing the filter media refers to a different maintenance task, adding chemicals pertains to water treatment and balancing, and draining the pool involves removing water from the pool rather than cleaning the filter.