Darlly 50221 Spa Filter Cartridge
Replaces Unicel C-5621 · Filbur FC-3091
Darlly 50221 is a 22 sq ft spa filter cartridge, 5-3/16" x 11-7/8". It replaces Unicel C-5621 and Filbur FC-3091.
Specifications
| Darlly part number | 50221 |
|---|---|
| Outside diameter | 5-3/16" |
| Length | 11-7/8" |
| Top end cap | Closed w/ string Handle |
| Bottom end cap | 1-15/16" Open |
| Filter area | 22 sq ft |
| Type | Spa |
| Darlly description | Advanced Spa(original) |
Cross-reference
| Brand | Part numbers Darlly 50221 replaces |
|---|---|
| Unicel | C-5621 |
| Filbur | FC-3091 |
Older or other numbers that also point to this cartridge (not confirmed by a second source): PTL25 (Pleatco).
Other Darlly cartridges the same size
Same diameter and length. Check the end caps and area before swapping.
Questions
- What is the Darlly replacement for Unicel C-5621?
- Darlly 50221 replaces Unicel C-5621. Both are 5-3/16" in diameter and about 11-7/8" long.
- What size is Darlly 50221?
- Darlly 50221 is 5-3/16" in outside diameter and 11-7/8" long, with 22 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.