Staff Answer
Jul 28, 2026 - 10:34 AM
The blue (post carbon) and grey/silver (VOC post carbon) filters occupy the same position in the Watts Pure/Pure Plus RO system. The earlier version, the RO Pure, which used Red, Yellow, Green, and Blue filters. The blue and silver/grey filters are interchangeable. The annual filter pack includes 5 filters—2 red (sediment, changed every 6 months), 2 yellow (pre-carbon, every 6 months), and 1 silver/blue (post-carbon, yearly)—but excludes the green (RO membrane) because the membrane, such as the Watts Pure H2O RO Membrane Filter, only needs replacement every 2-5 years, not annually.
