PA50 / C-7656 / FC-1240
50 sq ft replacement filter cartridge • 7″ OD × 19.625″ long
The PA50 is the single cartridge for Hayward's Star-Clear C500 pool filter, a 50-square-foot element that's 7 inches across and just under 20 inches tall, with 3-inch openings on both ends. Hayward's own number is CX500-RE. It also crosses to Pentair R173409 and Purex 27-079, plus Unicel C-7656 and Filbur FC-1240. The Star-Clear series runs one cartridge per tank, so replacement is simple, with no matched sets to worry about. Match the length to be sure, since the C500, C750, and larger Star-Clear tanks all use the same 7-inch diameter but progressively taller cartridges.
Compare on Amazon
PA50 replacements on Amazon
The buttons below pull up Amazon results for each cross-reference part number. Same physical cartridge, different stickers, often different prices. Cross-shop and pick the cheapest option that has solid recent reviews.
Cross-Reference & Interchangeable Part Numbers
| Brand | Part Number | Type |
|---|---|---|
| Pleatco | PA50 | Primary |
| Unicel | C-7656 | Equivalent |
| Filbur | FC-1240 | Equivalent |
| OEM | Hayward CX500-RE | Original Equipment |
| OEM | Pentair R173409 | Original Equipment |
| OEM | Purex 27-079 | Original Equipment |
Always verify dimensions and end-cap type before purchasing a replacement.
Compatible Pool Filter Systems
| Brand | Model |
|---|---|
| Hayward | Star-Clear C500 |
Frequently Asked Questions
What are the dimensions of the PA50?
The PA50 is 7 inches in outer diameter, 19.625 inches long, with an open top and an open bottom. Total filtration area is 50 square feet. Before ordering, pull your existing cartridge and measure it yourself, or check the label inside the housing. OD and length both have to match within about an eighth of an inch, and the end-cap style needs to match exactly so the cartridge seats properly when the lid closes.
What other part numbers are interchangeable with the PA50?
PA50 is the same physical cartridge as C-7656, FC-1240, plus OEM versions like Hayward CX500-RE, Pentair R173409, Purex 27-079. Same dimensions (7" × 19.625"), same open top, same open bottom. The Pleatco, Unicel, and Filbur boxes ship the same media inside, just with different stickers. The only thing to watch is the end-cap style: if a cross-reference has a slightly different cap design, it may not seat right in your housing.
Is the Hayward CX500-RE the same filter as the PA50?
Yes. Hayward CX500-RE is an OEM number, the code the tub or pool builder stamps on the cartridge they ship. The filter itself is made by Pleatco, Unicel, or Filbur, so Hayward CX500-RE (along with Pentair R173409, Purex 27-079) and PA50, C-7656, FC-1240 all point to one interchangeable cartridge. Buy whichever is cheapest with solid recent reviews, and just check that the dimensions match your old cartridge before you order.
How often should I replace the PA50?
At 50 sq ft the PA50 runs smaller than the big 100-plus sq ft pool cartridges, so it has less buffer between cleanings. Expect 12 to 18 months in normal use, less if the pool sees heavy traffic or the chemistry drifts. Watch the gauge: when pressure sits 8 to 10 psi above the clean starting point and a soak won't drop it, put in a fresh one.
How do I clean the PA50?
The PA50 has open ends on both top and bottom, so water flows straight through. Pull the cartridge from the housing and hose it down. Hit the pleats from above at about a 45-degree angle so water rinses debris out instead of packing it deeper, and work top to bottom while rotating the cartridge. Skip the pressure washer. The high pressure tears or collapses pleats, and once that happens you've lost media that doesn't come back. Every few months, give it a deeper clean: soak in a dedicated pool filter cleaner per the product's dwell time, then rinse it down completely before reinstalling. Keeping a spare cartridge on the shelf is genuinely worth it. You swap, run the soak overnight, and the pool keeps filtering.
Which hot tubs and spas use the PA50?
Pull your existing cartridge and read the part number off the end cap, or check the label inside the filter compartment. That's the most reliable way to confirm compatibility.
Dimensions
Specifications
| Outer Diameter | 7″ |
|---|---|
| Length | 19.625″ |
| Top Type | Open (no end cap) |
| Bottom Type | Open (no end cap) |
| Filtration Area | 50 sq ft |
| Primary Brand | Pleatco |
| Part Number | PA50 |
Fitment notes
3-inch top and bottom openings. Hayward Star-Clear C500.