Darlly 80503 Spa Filter Cartridge
Replaces Unicel 8CH-950 (now 8CH-951, 40 sq ft) · Pleatco PBF35 (Bullfrog 2003-2012 short thread) · Filbur FC-0536
- Diameter × length
- 8" × 6"
- Filter area
- 50 sq ft
- End caps
- semi-circular Handle / 2" SAE thread
- Per filter
- 1 cartridge
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 80503 is a 50 sq ft spa filter cartridge, 8" x 6". It fits the Bullfrog spas made 2003-2012 (short-thread filter). It replaces Unicel 8CH-950 (now 8CH-951, 40 sq ft), Pleatco PBF35 (Bullfrog 2003-2012 short thread), Filbur FC-0536, Bullfrog Spas 10-2785 and Bullfrog Spas 10-1035.
Specifications
| Darlly part number | 80503 |
|---|---|
| Outside diameter | 8" |
| Length | 6" |
| Top end cap | semi-circular Handle |
| Bottom end cap | 2" SAE thread |
| Filter area | 50 sq ft |
| Type | Spa |
| Blue antimicrobial version | 80503M |
| Darlly description | Bullfrog Spas |
Cross-reference
| Brand | Part numbers Darlly 80503 replaces |
|---|---|
| Unicel | 8CH-950 (now 8CH-951, 40 sq ft) |
| Pleatco | PBF35 (Bullfrog 2003-2012 short thread) |
| Filbur | FC-0536 |
| Hurricane (former brand) | HF8H950-01 |
| OEM and other numbers | Bullfrog Spas 10-2785, Bullfrog Spas 10-1035 |
Older or other numbers that also point to this cartridge (not confirmed by a second source): PBF50 (Pleatco).
Filters it fits
| Filter | Cartridges per filter | OEM cartridge number |
|---|---|---|
| Bullfrog spas made 2003-2012 (short-thread filter) | 1 | 10-2785, 10-1035 |
Bullfrog spas made 2013-2017 have a long-thread filter (Bullfrog 10-2870, Pleatco PBF36). Ask Darlly before ordering 80503 for one of those.
Bullfrog spas with the coreless filter (2017 and later) take Darlly 70361.
Questions
- What is the Darlly replacement for Unicel 8CH-950?
- Darlly 80503 replaces Unicel 8CH-950, which Unicel replaced with 8CH-951, a 40 sq ft cartridge. Both are 8" in diameter and about 6" long.
- What Darlly cartridge replaces Pleatco PBF35?
- Darlly 80503 replaces Pleatco PBF35.
- What size is Darlly 80503?
- Darlly 80503 is 8" in outside diameter and 6" 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.