Pentek - WS-20BB - 20" x 4.5" Water Softening Resin Filter
WS-20BB 20" x 4.5" Softening Resin Cartridge
Sodium-form cation exchange resin in a drop-in cartridge for point-of-use water softening
The Pentek WS-20BB delivers water softening in a standard cartridge format, eliminating the need for a full softener tank. Sodium-form cation exchange resin captures hardness minerals like calcium and magnesium, reducing scale buildup in appliances, fixtures, and equipment where hard water is a problem.
Ion Exchange Softening Process
Sediment Pre-Filter Layer
Polypropylene pre-filter captures particulate matter before water reaches the resin bed, preventing fouling and maintaining efficiency.
Cation Resin Bed
Sodium-charged resin beads exchange sodium ions for hardness-causing calcium and magnesium, reducing scale formation up to 4,500 grains total capacity.
77,000 PPM TDS capacityPost-Filter Protection
Polypropylene post-filter retains resin fines and ensures only softened, clean water exits the cartridge at up to 2.0 gallons per minute.
WS-20BB Technical Details
| Model Number | WS-20BB (Pentek 155321-03) |
| Dimensions | 20" x 4.5" (Big Blue) |
| Softening Capacity | 4,500 grains (as CaCO3) |
| Total TDS Capacity | 77,000 PPM |
| Flow Rate | 2.0 GPM maximum |
| Filter Media | Sodium-form cation exchange resin |
| Housing Material | Polypropylene shell and end caps |
| Gasket Material | Buna-N |
| Temperature Range | 40°F to 100°F |
Housing Requirements
The Pentek WS-20BB fits all standard 20-inch Big Blue filter housings with 4.5-inch inner diameter. Ideal for point-of-use applications including ice makers, dishwashers, coffee equipment, and small water heaters where hard water causes scaling. This cartridge is non-regenerable and should be replaced when softening capacity is exhausted, typically indicated by scale formation or hardness testing. Not intended for whole-house softening or drinking water applications where sodium content is a concern.
WS-20BB 20" x 4.5" Softening Resin Cartridge
Sodium-form cation exchange resin in a drop-in cartridge for point-of-use water softening
The Pentek WS-20BB delivers water softening in a standard cartridge format, eliminating the need for a full softener tank. Sodium-form cation exchange resin captures hardness minerals like calcium and magnesium, reducing scale buildup in appliances, fixtures, and equipment where hard water is a problem.
Ion Exchange Softening Process
Sediment Pre-Filter Layer
Polypropylene pre-filter captures particulate matter before water reaches the resin bed, preventing fouling and maintaining efficiency.
Cation Resin Bed
Sodium-charged resin beads exchange sodium ions for hardness-causing calcium and magnesium, reducing scale formation up to 4,500 grains total capacity.
77,000 PPM TDS capacityPost-Filter Protection
Polypropylene post-filter retains resin fines and ensures only softened, clean water exits the cartridge at up to 2.0 gallons per minute.
WS-20BB Technical Details
| Model Number | WS-20BB (Pentek 155321-03) |
| Dimensions | 20" x 4.5" (Big Blue) |
| Softening Capacity | 4,500 grains (as CaCO3) |
| Total TDS Capacity | 77,000 PPM |
| Flow Rate | 2.0 GPM maximum |
| Filter Media | Sodium-form cation exchange resin |
| Housing Material | Polypropylene shell and end caps |
| Gasket Material | Buna-N |
| Temperature Range | 40°F to 100°F |
Housing Requirements
The Pentek WS-20BB fits all standard 20-inch Big Blue filter housings with 4.5-inch inner diameter. Ideal for point-of-use applications including ice makers, dishwashers, coffee equipment, and small water heaters where hard water causes scaling. This cartridge is non-regenerable and should be replaced when softening capacity is exhausted, typically indicated by scale formation or hardness testing. Not intended for whole-house softening or drinking water applications where sodium content is a concern.
Original: $134.81
-65%$134.81
$47.18Description
WS-20BB 20" x 4.5" Softening Resin Cartridge
Sodium-form cation exchange resin in a drop-in cartridge for point-of-use water softening
The Pentek WS-20BB delivers water softening in a standard cartridge format, eliminating the need for a full softener tank. Sodium-form cation exchange resin captures hardness minerals like calcium and magnesium, reducing scale buildup in appliances, fixtures, and equipment where hard water is a problem.
Ion Exchange Softening Process
Sediment Pre-Filter Layer
Polypropylene pre-filter captures particulate matter before water reaches the resin bed, preventing fouling and maintaining efficiency.
Cation Resin Bed
Sodium-charged resin beads exchange sodium ions for hardness-causing calcium and magnesium, reducing scale formation up to 4,500 grains total capacity.
77,000 PPM TDS capacityPost-Filter Protection
Polypropylene post-filter retains resin fines and ensures only softened, clean water exits the cartridge at up to 2.0 gallons per minute.
WS-20BB Technical Details
| Model Number | WS-20BB (Pentek 155321-03) |
| Dimensions | 20" x 4.5" (Big Blue) |
| Softening Capacity | 4,500 grains (as CaCO3) |
| Total TDS Capacity | 77,000 PPM |
| Flow Rate | 2.0 GPM maximum |
| Filter Media | Sodium-form cation exchange resin |
| Housing Material | Polypropylene shell and end caps |
| Gasket Material | Buna-N |
| Temperature Range | 40°F to 100°F |
Housing Requirements
The Pentek WS-20BB fits all standard 20-inch Big Blue filter housings with 4.5-inch inner diameter. Ideal for point-of-use applications including ice makers, dishwashers, coffee equipment, and small water heaters where hard water causes scaling. This cartridge is non-regenerable and should be replaced when softening capacity is exhausted, typically indicated by scale formation or hardness testing. Not intended for whole-house softening or drinking water applications where sodium content is a concern.
