Description
Two-Stage Big Blue Sediment Filter with Dual Gradient Micron Ratings
Overview
The Franklin FWPS-DG Series is a dual gradient spun poly filter cartridge that performs two stages of sediment filtration in a single cartridge. Instead of one micron rating, the FWPS-DG uses paired ratings (like 50/5) where each number represents a different layer of the cartridge. This design extends service life in water with mixed coarse and fine sediment. It does not remove chlorine, chemicals, or taste and odor.
20" x 4.5" OD Big Blue format. Three dual-gradient micron options: 25/1, 50/5, and 75/25. 100% melt blown micro-denier polypropylene, thermally bonded without adhesives. NSF 42 and FDA CFR Title 21 certified. Sold individually or in cases of 6. Also available in 10" x 4.5" Big Blue.
Key Features
- Dual gradient density uses two distinct filtration stages in one cartridge. The outer layer shields the inner layer from premature loading, which extends total service life.
- 100% polypropylene micro-denier fiber, thermally bonded without adhesives, binders, or surfactants.
- Chemically resistant. Will not add taste, odor, or color to water. Resistant to bacterial attack.
- NSF 42 and FDA CFR Title 21 certified for potable water and food contact applications.
How Dual-Gradient Micron Ratings Work
A standard sediment filter has one micron rating across the entire cartridge. The FWPS-DG has two. The first number is the outer layer rating. The second number is the inner layer rating.
- 25/1: Outer layer captures particles 25 microns and larger. The inner layer captures particles down to 1 micron. Use for fine sediment removal where high clarity is needed.
- 50/5: Outer layer captures 50 microns and larger. The inner layer captures down to 5 microns. General purpose for most commercial and residential systems.
- 75/25: Outer layer captures 75 microns and larger. The inner layer captures down to 25 microns. First-stage pre-filter for heavy sediment loads or protection of downstream equipment.
The outer layer acts as a built-in pre-filter. In a single-rated cartridge, all particles hit the same media at once and the fine pores clog first. In the dual gradient design, the outer layer strips out the coarse material before it reaches the fine inner layer, which extends the cartridge's total service life.
Specifications
| Specification | Detail |
|---|---|
| Series | FWPS-DG |
| Cartridge Size | 20" x 4.5" OD (Big Blue) |
| Part Numbers | FWPS20B2501 (25/1), FWPS20B5005 (50/5), FWPS20B7525 (75/25) |
| Media | 100% melt blown micro-denier polypropylene |
| Construction | Dual gradient, thermal bonded |
| Micron Ratings | 25/1, 50/5, 75/25 |
| Max Operating Temperature | 60°C (140°F) |
| Nominal Replacement ΔP | 1.5 Bar (22 psi) |
| Max Pressure Drop @ 20°C | 3.2 Bar (46.4 psi) |
| Max Flow Rate | 20 GPM (75 lpm) |
| Inner Diameter | 28 mm (1.1") |
| Certifications | NSF 42, FDA CFR Title 21 |
| Case Quantity | 6 filters |
Compatible Housings
Fits any standard 20" Big Blue housing designed for 4.5" OD cartridges, including housings from Pentek, Culligan, Aqua-Pure, GE, iSpring, and most whole-house and commercial filter systems. Confirm your housing accepts a 20" x 4.5" OD cartridge.
Applications
- Commercial and industrial water treatment systems
- Whole-house sediment filtration
- Reverse osmosis pre-filtration
- Food and beverage processing
- Process water and chemical processing
- Water purification systems
- Electroplating operations
Buy Dual Gradient Sediment Filters from Cleanflow
Cleanflow stocks the Franklin FWPS-DG dual gradient spun poly filter cartridge in all three micron ratings as part of the Franklin Water catalog. Available individually or by the case (6 filters). Also available in 10" x 4.5" Big Blue. For single-rated alternatives, see the standard FWPS 20" Big Blue or FWSW string wound Big Blue as a water filter replacement option.
Free shipping on orders over $199. 30-day return policy. Ships across Canada and the United States. Email info@cleanflow.ca for volume orders, returns, or help choosing the right micron rating.
Frequently Asked Questions
What does a dual-gradient micron rating like 50/5 mean?
The first number (50) is the outer layer's micron rating. The second number (5) is the inner layer's rating. A 50/5 cartridge captures particles 50 microns and larger on the outside and particles down to 5 microns on the inside. See the rating guide above for help choosing between 25/1, 50/5, and 75/25.
How is the FWPS-DG different from the standard FWPS?
The standard FWPS has a three-layer gradient with a single micron rating (1, 5, 20, or 50). The FWPS-DG has two distinct filtration stages with paired micron ratings (25/1, 50/5, 75/25). The dual gradient holds more dirt in heavy-sediment water because the outer pre-filter layer extends the inner layer's service life.
How often should I replace this filter cartridge?
Replace when the pressure drop across the cartridge reaches 1.5 Bar (22 psi). In typical use, this is every 3 to 6 months depending on sediment load and flow rate. The dual gradient design extends replacement intervals compared to single-rated cartridges in the same water conditions because the outer layer handles the coarse sediment that would otherwise shorten filter life.
Can the FWPS-DG replace a standard single-rated Big Blue cartridge?
Yes. The FWPS-DG is a direct physical replacement for any standard 20" x 4.5" OD Big Blue sediment filter cartridge. It fits the same housings. Choose the dual-gradient option when your water carries a mix of coarse and fine sediment and you want longer service intervals.
Manuals & Documentation
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