Darlly 81504 Pool Filter Cartridge
Replaces Unicel C-8416 · Pleatco PWWPC150B (now ULTRA-B5) · Filbur FC-2576
- Diameter × length
- 8-15/16" × 28-3/16"
- Filter area
- 150 sq ft
- End caps
- 4" Open w/ molded gasket / 4" Open w/ molded gasket
- 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 81504 is a 150 sq ft pool filter cartridge, 8-15/16" x 28-3/16". It fits the Sta-Rite Posi-Clear PXC-125 (150 sq ft element) and Waterway Pro-Clean 150 with the 28-3/16" cartridge (817-0150P). It replaces Unicel C-8416, Pleatco PWWPC150B (now ULTRA-B5), Filbur FC-2576, Sta-Rite 25230-0150S and Waterway 817-0150P.
Specifications
| Darlly part number | 81504 |
|---|---|
| Outside diameter | 8-15/16" |
| Length | 28-3/16" |
| Top end cap | 4" Open w/ molded gasket |
| Bottom end cap | 4" Open w/ molded gasket |
| Filter area | 150 sq ft |
| Type | Pool |
| Darlly description | Sta-Rite PXC-125, Waterway Pro Clean 150 |
Cross-reference
| Brand | Part numbers Darlly 81504 replaces |
|---|---|
| Unicel | C-8416 |
| Pleatco | ULTRA-B5, PWWPC150B (now ULTRA-B5) |
| Filbur | FC-2576 |
| OEM and other numbers | Sta-Rite 25230-0150S, Waterway 817-0150P |
Filters it fits
| Filter | Cartridges per filter | OEM cartridge number |
|---|---|---|
| Sta-Rite Posi-Clear PXC-125 (150 sq ft element); Waterway Pro-Clean 150 with the 28-3/16" cartridge (817-0150P) (150 sq ft filter) | 1 | 25230-0150S, 817-0150P |
81253 (125 sq ft) and 81504 (150 sq ft) both fit the Posi-Clear PXC-125. Pro-Clean 150 shipped with two cartridge lengths. Measure yours: 23-5/16" takes 81502, 28-3/16" takes 81504.
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-8416?
- Darlly 81504 replaces Unicel C-8416. Both are 8-15/16" in diameter and about 28-3/16" long.
- What Darlly cartridge replaces Pleatco ULTRA-B5?
- Darlly 81504 replaces Pleatco ULTRA-B5.
- What size is Darlly 81504?
- Darlly 81504 is 8-15/16" in outside diameter and 28-3/16" long, with 150 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.