Hydro Guard HDGT-CB5 Twist Carbon Block Replacement Filter, 5 Micron, Activated Carbon Block, Stage 2 Pre-Filter for HDGT-45 Reverse Osmosis Water Filter System

The Hydro Guard HDGT-CB5 is the Stage 2 carbon block pre-filter for the HDGT-45 reverse osmosis system family. Constructed from activated carbon block media at a 5-micron rating, the HDGT-CB5 sits between the Stage 1 sediment filter and the Stage 3 RO membrane. Chlorine present in treated municipal water supplies are effective disinfectants, but they can degrade the thin film composite (TFC) material used in RO membranes when they come into sustained contact with it. By reducing these substances at Stage 2, the HDGT-CB5 helps protect the membrane and preserve its performance and service life. Unlike granular activated carbon (GAC) media, carbon block construction compresses the carbon into a solid matrix, ensuring consistent contact time between the water and the filtration media across the entire filter bed. Replacement is recommended every 6 to 12 months and is typically performed at the same time as the HDGT-SED5 sediment filter. The HDGT-CB5 uses Hydro Guard's quick twist-and-lock design for tool-free installation — no wrench and no plumber required. Compatible with Hydro Guard HDGT-45CP, HDGT-45CP38, HDGT-45BN, HDGT-45BN38, and HDGT-45CP-P reverse osmosis systems. Sold individually. Confirm your system model number before purchasing.