It's time to replace the filter cartridge or water purifier with your FT Line 1, FT Line 2, FT Line 3, FT Line PRE, FT Line VE or FT Line BASIC filters. If you were satisfied with the result, order the same cartridge by their number. If the water quality has worsened in the meantime and the initial cartridges are no longer sufficient, you can opt for cartridges with a higher level of filtration or purification.