Sundance and Jacuzzi look-alike filters: core plugs, bottom holes and handles

Last reviewed October 27, 2026

Several Sundance and Jacuzzi cartridges share a body and not a detail Unicel bothers to print. C-8326 and C-8327 are both 8-7/16" × 19", 125 sq ft, OEM 6540-488; Unicel says C-8326 has a core plug and fits spas before 2006, and C-8327 has no core plug and fits spas after 2005^[5]. C-7465 and C-7466 are both 7-1/2" × 14-3/4" castle-top cartridges at 65 sq ft; the bottom opening is 2-1/16" (OEM 6540-480) or 2-5/8" (OEM 6540-481)^[5]. Match the OEM number, then the note in the spec table.

The 125 sq ft pair: core plug or no core plug

C-8326 and C-8327 are the cartridges people shorten to “the big Sundance filter.” The spec rows print the same outside size and the same ends: 8-7/16" diameter, 19" long, a 1-1/2" male slip fitting on top, and a 2-1/2" open bottom with a beveled edge. Both are rated 125 sq ft. Both are tied to OEM 6540-488. Pleatco lists PSD125-2000 and Filbur lists FC-2780 against that OEM number^[5][2][31].

Unicel still splits them. The note on C-8326 says it contains a core block or plug, and the fitment Unicel gives is Sundance spas before 2006. The note on C-8327 says there is no core block or plug, the fitment is Sundance spas after 2005, and Unicel also prints OEM 6540-507 on that row. A Leisure Time listing describes C-8326 and C-8327 as the same cartridge^[44]. Unicel does not. When a dealer treats them as one part and the manufacturer’s filter guide treats the plug as the difference, keep the plug. Look down the core of the old cartridge. If your spa is dated before 2006 and the cartridge you removed has the plug, C-8326 is the row Unicel points at. If it is after 2005 and there is no plug, C-8327 is the row. If you cannot see a plug and cannot date the spa, order by the full OEM number on the cap (6540-488 or 6540-507) and compare the new cartridge with the old one before you install it.

The 65 sq ft castle-top pair: the bottom hole changes

C-7465 and C-7466 are both 7-1/2" × 14-3/4", both have a castle top, and both are rated 65 sq ft. The bottom inside diameter is the spec line that changes.

Pleatco’s “-2” on PSD65-2 is doing the same job as the different OEM number: it marks the larger bottom opening. Filbur splits them into FC-2730 and FC-2740^[31]. A castle top tells you that you are in this family. It does not tell you which bottom you have. Measure the open end, or read 6540-480 versus 6540-481. The fitting guide open-end vs threaded filters shows the same pattern on other brands.

Same OEM numbers, different top: 6CH-960 and 6CH-961

Jacuzzi 6CH-960 and 6CH-961 are both 6-3/4" × 15-1/2" cartridges with a 2" SAE thread, and Unicel prints the same OEM set on both rows: 6540-164, 6540-476 and 6541-383. The area on the rows is 75 sq ft, with a note that square footage is 75 or 60 depending on the OEM part number^[5]. The tops differ. 6CH-960 is printed with a semi-circular handle. 6CH-961 is printed “open with slots,” and Unicel says it requires an injection-molded semi-circular handle that is not furnished. Pleatco splits them into PJW60TL-F2S and PJW60TL-OT-F2S. Filbur lists FC-2800 and FC-2715. If your old cartridge has the handle molded on, you are looking at the 6CH-960 description. If the top is open and the handle is a separate piece, you are looking at the 6CH-961 description. Ordering the one that does not include the handle, when yours is molded on, gives you a cap you did not have before.

One Jacuzzi OEM number printed on two areas

Jacuzzi OEM 373045 appears on two open-end cartridges of the same body size and different media area: C-4326 at 25 sq ft and C-4950 at 50 sq ft. Both are 4-15/16" × 13-5/16" with 2-1/8" open ends. The note on the C-4950 row says the same OEM part number is listed for 25 and 50 sq ft^[5]. This is the upgrade pattern Unicel describes elsewhere: more pleats in the same can, which is the subject of why same-size filters have different square-foot ratings. Pleatco lists PRB25-IN and PRB50-IN for that size family. If the only number you have is 373045, you still have to know whether the cartridge you removed is the 25 sq ft or the 50 sq ft version. Count the pleats if the printing is gone. Unicel’s own lookup instructions include a pleat count within about two pleats^[5].

J-460 and the shared 6540-series numbers

Sundance and Jacuzzi Premium share a large family of 6540-series OEM numbers. Sundance 5CH-402 and Jacuzzi 5CH-402 are both OEM 6540-723: 5-3/16" × 10-3/4", bar handle, 2" male MPT, 50 sq ft. Sharing the number across the two brands means the cartridge is the same row, not that every Jacuzzi takes every Sundance cartridge.

The opposite warning is on the J-460. Leisure Time’s listing for 6CH-945 (OEM 6540-498, 6" × 13-1/2", 2" SAE, 45 sq ft, Pleatco PJP45-F2S) says J-460 spas used several cartridges that are not interchangeable, and that you should confirm size and thread against the old filter^[45]. A J-460 owner who orders “the J-460 filter” from a single photo has not finished the job. Measure length and look at the thread. The Jacuzzi model-year lookup and the Sundance lookup are the indexes. All Jacuzzi cartridges and all Sundance cartridges are the full tables.

What to write down

1. The full OEM number, including 6540-488 versus 6540-507, 6540-480 versus 6540-481, and 6540-164 versus the other numbers on that cap.
2. Whether you can see a core plug.
3. The bottom opening or the thread, measured, not guessed from the length.
4. Whether the handle is molded on or is a separate piece.
5. The year of the spa when the Unicel note is “before 2006” or “after 2005.”

Installation after you have the match is covered in how to install a hot tub filter. If the spa throws a flow code the first time the new cartridge runs, the code list is in flow errors and the filter.

Questions

Sources

2. Pleatco 2023 Catalog (Pentair)
4. Unicel: Maintenance & FAQ
5. Unicel 2026 Replacement Guide
31. Filbur Catalog & Reference Guide
44. Leisure Time Inc.: Unicel C-8327 filter cartridge
45. Leisure Time Inc.: Unicel 6CH-945 filter cartridge (Jacuzzi J-460)

This guide summarizes published manufacturer and public-health guidance; always follow your own spa’s owner’s manual. See our disclaimer.