Filter and softener, one tank
Purest Flow X4
KDF55, catalytic carbon and softening resin layered in one tank, with a brine tank and metered regeneration.
What it does
KDF55, catalytic carbon and softening resin in one tank. Filtration and true softening, together.
- Reduces hardness minerals through ion-exchange softening
- Reduces chlorine and chloramines
- Reduces volatile organic compounds and trihalomethanes (THMs)
- Reduces selected dissolved metals
- Reduces tastes and odors
- Helps protect plumbing and appliances from scale
How it works
KDF55
Supports reduction of free chlorine and selected water-soluble metals. Its bacteriostatic properties help control growth within the media bed and protect the carbon downstream.
Catalytic carbon
Adsorbs organic compounds and targets chlorine, chloramines, VOCs, THMs, tastes, odors and hydrogen sulfide. Backwashing cleans and redistributes the media.
Softening resin
Ion-exchange resin removes calcium and magnesium hardness. It can also address low levels of iron and manganese when water conditions are appropriate.
Benefits
Two treatment goals
Filtration plus true hardness removal.
Efficient operation
Metered regeneration responds to water use.
Separated media
Mid-plate and bottom-plate construction supports proper media placement.
Professional programming
Settings are matched to your water conditions and household demand.
Serviceable platform
Backwashing carbon and regenerating resin help maintain treatment performance.
Specs
| Base model | Carbon (ft³) | Softening media (ft³) | KDF55 (lb) | Mineral tank | Service flow (gpm) | Valve |
|---|---|---|---|---|---|---|
| 32KMXCAT | 0.50 | 1.0 (32K) | 3 | 10x54 | 5 | Clack WS1 |
| 48KMXCAT | 1.0 | 1.5 (48K) | 6 | 13x54 | 10 | Clack WS1 |
| Specification | 1-inch series |
|---|---|
| Inlet/outlet | 3/4 to 1.5 inch NPS adapter |
| Cycles | Up to 5 |
| Valve material | Fiber-reinforced composite |
| Regeneration | Downflow / upflow |
| Operating pressure | 20-125 psi |
| Operating temperature | 40-110 F |
Each configuration includes single-tank mid-plate and bottom-plate construction and a 15 x 17 x 36 inch brine tank.
Clack WS1 valve: an American-made control valve platform. A battery backup helps keep the clock accurate during a power outage. One programming family supports 1, 1.25 and 1.5 inch valve sizes, twelve preset programs are available, and metered control supports demand-based regeneration.
Source: Purest Dealer Group technical data sheet, rev 09/2026. Capabilities depend on source-water chemistry, flow demand, programming, media configuration and proper installation.
Which homes it fits
The Flow X4 suits homes that want filtered and softened water from one tank. The free water test shows whether your water needs both.
Questions about the Purest Flow X4
It combines ion-exchange softening with KDF55 and catalytic carbon filtration. It is designed to reduce hardness minerals, chlorine, chloramines, volatile organic compounds, trihalomethanes, selected dissolved metals, tastes and odors.
Hard water produces scale. Calcium and magnesium can leave build-up on fixtures, glass and appliances, and can increase soap use and reduce lather.
Yes. The X4 is salt based, so it needs salt, power and a drain. The brine tank holds the salt that recharges the softening resin during regeneration.
Regeneration is metered, so it follows your water use. Backwashing keeps the carbon clean, and settings are matched to your water and household.
Two configurations. The 32KMXCAT has a 10x54 mineral tank and a 5 gpm service flow. The 48KMXCAT has a 13x54 mineral tank and a 10 gpm service flow.
The Clack WS1 valve has a battery backup that helps keep the clock accurate during a power outage.
Book a free water test
A free in-home test shows hardness, chlorine, iron, total dissolved solids and pH before we recommend anything.