What is the Darlly replacement for Unicel C-4603?

Darlly 40091 replaces Unicel C-4603. Both are 4-1/4" in diameter and about 10-7/8" long.

What size is Darlly 40091?

Darlly 40091 is 4-1/4" in outside diameter and 10-7/8" long, with 9 sq ft of filter area.

Darlly 40091 Spa Filter Cartridge

Replaces Unicel C-4603

Darlly 40091 is a 9 sq ft spa filter cartridge, 4-1/4" x 10-7/8". It replaces Unicel C-4603.

Specifications

Darlly part number	40091
Outside diameter	4-1/4"
Length	10-7/8"
Top end cap	1-15/16" Open
Bottom end cap	1-15/16" Open
Filter area	9 sq ft
Type	Spa
Darlly description	Haugh's, Jacuzzi Leisure C-11

Cross-reference

Brand	Part numbers Darlly 40091 replaces
Unicel	C-4603

Older or other numbers that also point to this cartridge (not confirmed by a second source): PHP11 (Pleatco), FC-3756 (Filbur).

Questions

What is the Darlly replacement for Unicel C-4603?: Darlly 40091 replaces Unicel C-4603. Both are 4-1/4" in diameter and about 10-7/8" long.
What size is Darlly 40091?: Darlly 40091 is 4-1/4" in outside diameter and 10-7/8" long, with 9 sq ft of filter area.

Where to buy Darlly 40091

Pool and spa businesses in Florida, Georgia, South Carolina, Alabama, Mississippi, Louisiana and Texas order through their Grit Game rep. Everywhere else, contact Darlly Filtration directly.

Find your Grit Game rep Contact Darlly Darlly 40091 on darllyfilter.com

Cross-reference checked October 21, 2026 against Unicel's 2026 Replacement Guide, Pleatco's catalog (updated September 2025), filbur.com and darllyfilter.com. A competitor number is listed only when that brand's own data pairs it with the same cartridge size. Always compare the size and end caps of your old cartridge before ordering.

Brand names and part numbers are trademarks of their respective owners and are shown only to identify compatible replacements. Darlly Filtration is not affiliated with or endorsed by them. Cross-reference by The Grit Game, Darlly's sales agency.