Pentair FNS Plus 48
#5 in D.E.Full review
A grid D.E. filter for an in-ground pool of up to about 46,080 gallons, for owners who want the clearest water and will handle D.E.
Amazon $1,379$1,379
The Pentair FNS Plus 48 is the better pool filter overall, rated 3.5 to 3.0. The Pentair FNS Plus 48 leads on filter area and pressure rating. The Hayward Perflex EC40AC costs $810 less ($569 vs $1,379).
Hayward Perflex EC40AC
#10 in D.E.Full review
An extended-cycle D.E. filter for an above-ground or small in-ground pool, for owners who want D.E. clarity without a backwash valve.
Amazon $569$569
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Pentair FNS Plus 48 for filter area (48 sq ft of filter area vs 20 sq ft of filter area) and pressure rating (50 psi maximum working pressure vs 40 psi maximum working pressure).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every D.E. pool filter; a clear win is highlighted. How we rank explains each one.
| Factor weight | Pentair FNS Plus 48 | Hayward Perflex EC40AC |
|---|---|---|
| Overall rating | 3.5/5 | 3.0/5 |
| Value 35% | 61 $14.36 per gpm ($1,379, 96 gpm) | 62 $14.22 per gpm ($569, 40 gpm) |
| Filter area 30% | 54 48 sq ft of filter area | 0 20 sq ft of filter area |
| Valve 10% | 50 valve type not published (neutral score used) | 100 no backwash valve needed |
| Pressure rating 10% | 100 50 psi maximum working pressure | 50 40 psi maximum working pressure |
| Warranty 15% | 33 1-year warranty | 33 1-year warranty |
Specifications
| Pentair FNS Plus 48 | Hayward Perflex EC40AC | |
|---|---|---|
| Filtering | ||
| Filter type | D.E. | D.E. |
| Filter area | 48 sq ft | 20 sq ft |
| Maximum flow | 96 gpm | 40 gpm |
| Largest pool | 46,080 gal | 19,200 gal |
| Pool type | In-ground | In-ground or above-ground |
| Build | ||
| Tank diameter | 21.5 in | - |
| Valve | - | None needed |
| Maximum pressure | 50 psi | 40 psi |
| Ports | - | 1.5 in |
| Air relief | Yes | Yes |
| Warranty | 1 year | 1 year |