Spa and hot tub filter cross-reference
Type the number molded into your old filter, such as a Sundance 6540-476, a Unicel C-8326 or a Pleatco PTL47W. No number left? Type the size, diameter × length, like 7 x 10-3/4 or 178 x 273 mm. A spa brand or model works too.
Try 6540-476, 7 x 10-3/4 or Caldera.
Browse by spa brand
- Hot Spring
11 cartridges
- Hot Spot
5 cartridges
- Solana
1 cartridge
- Caldera
10 cartridges
- Jacuzzi
12 cartridges
- Sundance
17 cartridges
- Bullfrog
7 cartridges
- Cal Spas
9 cartridges
- Master Spas
13 cartridges
- Marquis Spas
9 cartridges
- Dimension One Spas
12 cartridges
- Nordic Hot Tubs
3 cartridges
- Softub
2 cartridges
- Intex
2 cartridges
- Bestway
1 cartridge
- Beachcomber
4 cartridges
- Strong Spas
1 cartridge
- Freeflow Spas
3 cartridges
- Freedom Spas
6 cartridges
- PDC Spas
7 cartridges
- Coleman Spas
12 cartridges
- Maax Spas
6 cartridges
- Waterway Plastics
12 cartridges
- Saratoga Spas
6 cartridges
When to replace or clean
- Replace and clean calculator
Published intervals from Hot Spring, Jacuzzi, Sundance, Unicel and Pleatco, turned into dates.
- Replacement schedule for one cartridge
The interval that applies to your cartridge, with its cross-reference numbers.
Sizing and fitting guides
- How to find your spa filter size
- Hot Spring filter sizes by collection: Highlife, Limelight and Tiger River
- Open-end vs threaded hot tub filters: how to tell which fitting you have
- Caldera filter bottoms: male slip, open end, and the 2014 Cantabria split
- How often should you replace a hot tub filter?
- Intex PureSpa and Bestway Lay-Z-Spa filters: S1, S2 and Type VI
Holiday 2026: Black Friday filters and spa care, gifts for hot tub owners, and winter spa care. Published dates and shipping cutoffs only.
How a match is made
Spa makers, Unicel, Pleatco and Filbur often number the same cartridge differently. Each cartridge page lines those numbers up from the published tables and links the catalog page. If a number is missing, or two catalogs disagree, the page says what is missing. Measure the old cartridge before you order: the measuring guide shows how.