Pentair FNS® Plus 36 Sq Ft D.E. Filter
The Pentair FNS® Plus 36 Sq Ft D.E. Filter is a vertical-grid diatomaceous earth filter engineered for superior filtration performance and extended time between cleanings. Curved grids maximize filtration area, while refined internal hydraulics minimize flow restriction — requiring minimal pumping power to achieve the needed flow rate. Built with fiberglass-reinforced polypropylene for superior strength and reliability.
Features the Service-Ease™ grid pack for simplified cleaning, top-to-bottom backwash, Tension Control™ clamp, Continuous High Flow™ internal air relief, and black valves and plumbing. ANSI Standard 50 certified. Backed by a 2-year warranty.
Key Features
36 Sq Ft D.E. Filtration
Curved grid design maximizes filtration area — finer filtration and longer cleaning intervals than the 48 sq ft model requires per pool size.
Finest Filtration Available
D.E. filtration removes particles down to 3–5 microns — the clearest water achievable from any filter type.
Service-Ease™ Grid Pack
Grid assembly lifts out as a single unit for faster, simpler annual teardowns and cleaning.
Top-to-Bottom Backwash
Efficient backwash cycle cleans grids thoroughly from top to bottom.
Continuous High Flow™ Internal Air Relief
Integrated automatic air relief plus manual High Flow™ air relief valve.
Tension Control™ Clamp
Secure, easy-to-operate clamp band for tank access.
Low Pumping Power Required
Refined internal hydraulics minimize flow restriction for energy-efficient operation.
100% Factory Tested
Every unit pressure-tested at the factory before shipment.
ANSI Standard 50 Certified / 2-Year Warranty
Certified performance and Pentair's 2-year residential warranty.
Who It's For
- Pool and spa owners who want D.E. water clarity in a smaller filter than the 48 sq ft FNS Plus
- Pools where 36 sq ft of D.E. is the correct size for their volume and flow rate
- Anyone upgrading from sand filtration who wants dramatically clearer water
- Pentair system users wanting brand-matched D.E. filtration
Specifications
Performance
| Filtration Area | 36 sq ft |
| Filter Type | Vertical-Grid D.E. |
Tank & Plumbing
| Tank Material | Fiberglass-Reinforced Polypropylene |
| Bulkhead Fittings | 7-1/2 in centerline |
| Clean-Out Port | 1-1/2 in bottom |
| Valve / Plumbing Color | Black |
Physical
| Product Weight | 70 lb |
| Shipping Dimensions | 22 × 22 × 33.5 in |
Approvals & Warranty
| Certifications | ANSI Standard 50 Certified |
| Warranty | 2 Years |
What's in the Box
- Pentair FNS Plus Filter Tank with Curved Grid Pack
- Tension Control Clamp
- User Manual
Note: Diatomaceous earth (D.E. powder) is not included and must be purchased separately.
Warranty
The Pentair FNS Plus 36 sq ft D.E. Filter comes with a 2-year manufacturer warranty. Clearflow Pool Supply is an authorized Pentair dealer and will assist with any warranty service needed.
Downloads
Frequently Asked Questions
What is the difference between the FNS Plus 36 (180007) and the FNS Plus 48 (180008)?
Both are Pentair FNS Plus curved-grid D.E. filters with identical features and 2-year warranties. The 36 sq ft model is correctly sized for smaller pools or lower bather loads; the 48 sq ft model is the step up for larger pools. The 48 sq ft ships slightly taller (45 in vs. 33.5 in) due to the additional grid area. Choose based on your pool's volume and required flow rate.
How much D.E. powder does this filter require?
The FNS Plus 36 sq ft typically requires approximately 5.4 lb of D.E. powder after backwashing or reassembly. Always follow the specific amount listed in the owner's manual and use pool-grade diatomaceous earth.
What is the Service-Ease grid pack?
The Service-Ease grid pack assembles all filter grids into a single unit that lifts out together rather than removing each grid individually. This makes annual teardowns and deep cleanings significantly faster and easier.