Description
Big Blue Water Filter Replacement in 4 Micron Ratings
Overview
This big blue string wound filter cartridge fits standard 4.5" OD Big Blue housings in 10" and 20" lengths. 100% FDA-grade polypropylene cord wound around a polypropylene core. Four micron ratings (1, 5, 20, 50) for fine to coarse sediment removal. Sold individually or in bulk packs: 12-pack for 10" cartridges, 6-pack for 20" cartridges.
Specifications
| Spec | Detail |
|---|---|
| Housing | 4.5" OD (Big Blue) |
| Lengths | 10" (9.88"), 20" |
| Microns | 1, 5, 20, 50 |
| Material | FDA polypropylene cord + core |
| Max Temp | 55°C (130°F) |
| Max Pressure Drop | 1.5 Bar (22 psi) |
| Replace At | 1.0 Bar (15 psi) ΔP |
| Box Qty | 12 (10") / 6 (20") |
Key Features
- FDA-grade polypropylene safe for potable water and food contact applications.
- String wound construction holds more sediment than spun or melt-blown cartridges before requiring replacement.
- Low pressure drop maintains system flow without forcing the pump to work harder.
- Fits most standard 4.5" Big Blue housings including GE, Culligan, Pentek, and Ametek.
Why String Wound Over Melt Blown
A melt blown filter is made from compressed thermoplastic fibers that form a dense, uniform mat. It captures very fine particles well, but the tight fiber structure fills with sediment faster. A string wound filter wraps polypropylene cord around a core in layers that get progressively tighter toward the center. The outer layers catch large particles first. The inner layers catch smaller particles. This gradient density creates a deeper filtration path, so the cartridge holds more total sediment before the pressure drop signals it needs replacing.
Choose string wound when the water carries heavy sediment: well water with sand, municipal water with rust or scale, or industrial process water with visible particles. A polypropylene sediment filter big blue cartridge like the FWSW handles these loads at a lower cost per unit than melt blown.
Choose melt blown when the water is relatively clean and you need to capture very fine particles below 5 microns, such as polishing water before an RO membrane in a low-sediment system.
Flow Rates by Size and Micron
Use the variant selector above to choose your configuration in three steps: length (10" or 20"), micron rating (1, 5, 20, or 50), and quantity (single filter or bulk pack). The 4.5 x 20 string wound filter delivers higher flow at every micron rating.
| Size (OD x Length) | Micron Rating | Nominal Flow Rate |
|---|---|---|
| 4.5" x 10" | 1 Micron | 10 GPM (38 lpm) |
| 4.5" x 10" | 5 Micron | 20 GPM (76 lpm) |
| 4.5" x 10" | 20 Micron | 20 GPM (76 lpm) |
| 4.5" x 10" | 50 Micron | 20 GPM (76 lpm) |
| 4.5" x 20" | 1 Micron | 30 GPM (114 lpm) |
| 4.5" x 20" | 5 Micron | 30 GPM (114 lpm) |
| 4.5" x 20" | 20 Micron | 30 GPM (114 lpm) |
| 4.5" x 20" | 50 Micron | 30 GPM (114 lpm) |
The 1 micron cartridge at 10" has the lowest flow (10 GPM) because finer filtration restricts more water. If your system requires higher throughput with fine filtration, choose the 20" length at 30 GPM.
Which Micron Rating Do You Need
- 1 micron: Finest filtration. Polishes water before RO membranes or point-of-use dispensers. Catches particles invisible to the naked eye.
- 5 micron: General purpose. Handles most well water and municipal sediment. The most common rating for residential and commercial systems.
- 20 micron: Coarse sediment. Works as a pre-filter to protect finer downstream cartridges from heavy sand or silt loads.
- 50 micron: First-stage filtration. Removes heavy sand, visible particles, and large debris from untreated or raw water sources.
Applications
- Municipal and residential potable water sediment removal
- Pre-filtration and post-filtration for reverse osmosis systems
- Food and beverage processing water
- Process and cooling water treatment
- Chemical processing fluid filtration
- Well water sediment control
Buy Big Blue String Wound Filters from Cleanflow
Cleanflow Utility Supply Company stocks the Franklin Water FWSW big blue string wound filter cartridge in all four micron ratings and both lengths as part of the Franklin Water catalog. Bulk packs available: 12-pack (10") and 6-pack (20"). Free shipping on orders over $199. Ships across Canada and the United States. Email info@cleanflow.ca for volume orders or help selecting the right micron rating for your system.
FAQs
What micron filter do I need for well water?
Start with 5 micron for most residential wells. If your water carries heavy sand or silt, add a 20 or 50 micron pre-filter upstream to extend the life of the 5 micron cartridge. For water feeding an RO system, finish with a 1 micron polypropylene sediment filter big blue cartridge to protect the membrane.
What is the difference between string wound vs pleated filter cartridge?
String wound cartridges hold more dirt per cartridge and cost less per unit. Pleated cartridges have more surface area and can be rinsed and reused. For high-sediment applications where you replace rather than clean, string wound filter cartridge Canada options like the FWSW series are the more cost-effective choice.
How often do you replace big blue filter cartridges?
Replace when the pressure drop across the cartridge reaches 1.0 Bar (15 psi), which the system's pressure gauge will show. In typical residential use, this is every 3 to 6 months. Heavy sediment loads or high flow rates shorten the interval.
What big blue housing does this filter fit?
Any standard 4.5" OD Big Blue housing. This includes housings from GE, Culligan, Pentek, Ametek, iSpring, and most other manufacturers that follow the industry-standard big blue water filter replacement cartridge dimensions. Confirm your housing takes a 10" or 20" cartridge before ordering. If your housing is 2.5" OD (standard size, not Big Blue), see the Franklin Water 2.5" OD string wound cartridges instead.
Manuals & Documentation
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