Pentair 180008 FNS Plus 48 D.E. Filter

The Pentair 180008 FNS Plus 48 D.E. Filter is a 48 sq. ft. vertical grid diatomaceous earth filter designed for high-quality pool water filtration and reliable everyday performance. It is a strong replacement option for older Pentair 4000 Series D.E. filters and is built to provide clean, clear water with the filtration quality D.E. systems are known for.

Product Overview

The FNS Plus 48 uses a fiberglass-reinforced polypropylene tank and a vertical grid design to capture fine debris from pool water. This model is ideal for pool owners who want powerful filtration, dependable flow, and serviceable components with current Pentair parts support.

Key Features

• 48 sq. ft. D.E. filter for excellent water clarity
• Vertical grid design helps capture fine particles and debris
• Fiberglass-reinforced polypropylene tank for long-term durability
• 2 inch plumbing connections for compatibility with many modern pool systems
• Easy service access for cleaning and maintaining the internal grid assembly
• Modern replacement option for many older Pentair D.E. filter installations

Recommended Use

This filter is commonly used on residential in-ground pools where strong filtration and clear water quality are a priority. The 48 sq. ft. size is a practical choice for many standard pool systems and can be a close modern replacement for older 48 sq. ft. Pentair D.E. filters.

Important Installation Note

This filter uses 2 inch plumbing connections, but some plumbing adjustment may still be needed depending on your current equipment layout. We recommend confirming your existing model, pool size, and plumbing setup before ordering.

Need Help Confirming Fit?

If you are replacing an older Pentair 4000 Series, SMBW, or other D.E. filter, please contact us before ordering. Send us a photo of your current filter label, your pool size, or your pool dimensions, and we can help confirm whether the Pentair FNS Plus 48 is the right replacement for your system.

Replacing an Older Pentair 4000 Series or SMBW Filter?

The Pentair FNS Plus 48 is one of the most common modern replacements for older Pentair 4000 Series and SMBW D.E. filters. If your existing filter tank is cracked, leaking, or no longer serviceable, upgrading to the FNS Plus series gives you a reliable, supported solution without changing your filtration type.

This model maintains the same D.E. filtration performance while improving serviceability and long-term parts availability.