When should RO elements be replaced?

The correct response regarding when reverse osmosis (RO) elements should be replaced is based on their performance and the levels of total dissolved solids (TDS) in the output water. RO elements are designed to filter out contaminants and reduce TDS; therefore, monitoring TDS levels is critical to determining their effectiveness.

When TDS exceeds 1000 parts per million (ppm), it indicates that the RO system is no longer effectively removing dissolved salts and other impurities from the water. This level serves as a threshold that suggests the RO membranes are either saturated or degraded to the point where they cannot perform optimally. Therefore, replacing the RO elements at this stage ensures the water quality remains high and meets necessary standards.

Other options do not align with best practices for RO system maintenance. For instance, replacing RO elements after every backwash cycle would be impractical and unnecessary as backwashing is meant to clean the system without needing to replace the membranes. Similarly, changing them when it’s time to add new chemicals does not correlate directly with the condition of the RO elements. Lastly, a fixed operational time like 20 hours does not take into account variations in water quality and usage, which can significantly affect the lifespan of RO membranes.

Thus, monitoring TDS levels