Darlly 40503 Spa Filter Cartridge
Replaces Unicel 4CH-50
- Diameter × length
- 4-5/8" × 14-3/4"
- Filter area
- 50 sq ft
- End caps
- Handle / 1.5" MPT
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.
Darlly 40503 is a 50 sq ft spa filter cartridge, 4-5/8" x 14-3/4". It replaces Unicel 4CH-50.
Specifications
| Darlly part number | 40503 |
|---|---|
| Outside diameter | 4-5/8" |
| Length | 14-3/4" |
| Top end cap | Handle |
| Bottom end cap | 1.5" MPT |
| Filter area | 50 sq ft |
| Type | Spa |
| Darlly description | top load |
Cross-reference
| Brand | Part numbers Darlly 40503 replaces |
|---|---|
| Unicel | 4CH-50 |
Older or other numbers that also point to this cartridge (not confirmed by a second source): PTL50 (Pleatco), FC-0151 (Filbur).
Questions
- What is the Darlly replacement for Unicel 4CH-50?
- Darlly 40503 replaces Unicel 4CH-50. Both are 4-5/8" in diameter and about 14-3/4" long.
- What size is Darlly 40503?
- Darlly 40503 is 4-5/8" in outside diameter and 14-3/4" long, with 50 sq ft of filter area.
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.