This fits your .
CARTRIDGE, WATER SOFTENER, (7SO) LOW WATER VOLUME APPLICATION, 2000 GRAIN CAPACITY 307599
From the Manufacturer
Softening cartridge reduces scale-forming minerals. Softening cartridge reduces hardness in water that can cause minerals to build-up in coffee and espresso equipment Properly sized precoat filter cartridge should be installed before 7SO cartridge for best results.
Everpure EV9607-04 7SO Softening Cartridge - B0051SQSF2