The Pentek RFFE20-BB is a Big Blue-sized iron reducing water filter cartridge specifically engineered to reduce dissolved (ferrous) iron from well water and municipal water supplies. It uses a proprietary Filox-R media blend that oxidizes soluble iron into insoluble particles, which are then trapped inside the cartridge. This helps eliminate rust-colored staining on fixtures, laundry, and appliances, as well as the metallic taste associated with iron-contaminated water.

The Pentek RFFE20-BB has a nominal micron rating designed to capture oxidized iron particulates while maintaining strong flow rates. It is rated to reduce ferrous iron levels up to 3 ppm (parts per million) and has a service capacity of approximately 1,500 gallons under typical well water conditions. For optimal performance, the incoming water should have a pH of 6.5 or higher and contain adequate dissolved oxygen.

The RFFE20-BB should be replaced every 3 to 6 months, or sooner if you notice a return of iron staining, metallic taste, or reduced water pressure. Replacement frequency depends on your iron concentration, daily water usage, and overall water chemistry. Households with higher iron levels (closer to the 3 ppm maximum) will typically need to replace the cartridge more frequently than homes with trace iron contamination.

The RFFE20-BB measures 20" x 4.5" (Big Blue size) and fits any standard 20-inch Big Blue whole house filter housing, including Pentek, Pentair, and other compatible 20" BB systems. It is ideal for point-of-entry (POE) whole house applications where iron reduction is needed before water reaches your plumbing fixtures and appliances. Always verify your housing dimensions and inlet/outlet configuration before installation.

The RFFE20-BB is purpose-built for ferrous iron reduction and is not designed to remove chlorine, fine sediment, bacteria, or chemical contaminants. For comprehensive whole house filtration, Pentek recommends installing the RFFE20-BB as part of a multi-stage system—typically paired with a sediment pre-filter to capture oxidized iron particulates and a carbon block post-filter for chlorine, taste, and odor reduction. This staged approach maximizes cartridge life and delivers cleaner, better-tasting water throughout your home.