FreshWater's Carbon Dealk water filter cartridge incorporates granular activated carbon, combined with 'dealk' resin. The Carbon Dealk cartridge is designed to remove chlorine and heavy metals. In addition, it also reduces the residues associated with hard water - namely limescale in kettles and scum on the surface of hot drinks.
Your Carbon Dealk filter cartridge will likely need to be replaced between 3-6 months however this does depend on the hardness of the water and volume of water used. Those in very hard water areas with higher water usage may need to change it more frequently.