Listing we opened and checked. Match the diameter, length and both fittings on this page before you order. The price is on Amazon; we do not print one.
Dimension One Spas OEM 1561-09 spa filter (C-5404)
Dimension One Spas (ozone cartridge)
Replacement numbers
Unicel C-5404, Pleatco PDO40-4
Fits Dimension One Spas OEM 1561-09.
Diameter 5-1/2" (140 mm)Length 17" (432 mm)40 sq ft1 model listedUnicel C-5404
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| Unicel | C-5404 |
|---|---|
| Pleatco | PDO40-4 (as printed in the Filbur catalog Dimension One Spas section (printed p.33); not found in the Pleatco 2023 Unicel cross reference) |
| Filbur | FC-3097 |
| Top | 1-15/16" (49 mm) / open w/ 12 concentric holes |
| Bottom | 2-7/8" (73 mm) / open |
Bottom: 2-7/8" (73 mm) / open
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 40 sq ft media.
For Dimension One Spas, C-5404 cartridge (OEM 1561-09) sits in Dimension One Spas (ozone cartridge). The cross-reference prints OEM 1561-09; Unicel C-5404; Pleatco PDO40-4; Filbur FC-3097. 5-1/2" across, 17" long, top 1-15/16" / open w/ 12 concentric holes, bottom 2-7/8" / open, 40 sq ft.
Catalog note for 1561-09: Ozone cartridge with 12 concentric holes in the top cap (Unicel and Filbur).
PDO40-4 is the Pleatco string Filbur prints next to C-5404 (OEM 1561-09) on printed p.33. PDO40-4 itself is absent from Pleatco’s 2023 Unicel cross-reference.
Model list attached to C-5404 cartridge (OEM 1561-09): Dimension One spas with the Crystal Pure water management system, no year range printed, listed by Hot Tub Outpost OEM listing.
C-5404 is easy to confuse on the Dimension One Spas table. 4CH-940 differs by Unicel 4CH-940, Pleatco PDO-UF40P2, Filbur FC-0177, 4-5/8" diameter, 15" long, top semi-circular handle, bottom 1-1/4" SAE thread, OEM 1561-13. 4CH-50 differs by Unicel 4CH-50, Pleatco PTL50P-4, Filbur FC-0151, 4-5/8" diameter, 14-3/4" long, top molded cone handle, bottom 1-1/2” male thread/MPT, 50 sq ft, OEM 1561-05.
Source locations for this Dimension One Spas row: Unicel 2026 Replacement Guide on C-5404 (OEM cross reference (Dimension One Spas section), PDF p.34 (printed p.30); spec table PDF p.11 (printed p.7)). Filbur Catalog & Reference Guide on C-5404 (Product by Pool/Spa Manufacturer (OEM), Dimension One Spas, printed p.33 (PDF p.17)). Hot Tub Outpost (retailer OEM listing) on C-5404 (1561-09: 5.5" x 17", 1-15/16" open top with 12 concentric holes, 2-7/8" open bottom; all spas with the Crystal Pure water management system; replaces Unicel C-5404, Filbur FC-3097, Pleatco PDO40-4).
Hot tubs listed for this cartridge
The rest of the Dimension One Spas model list is the Dimension One Spas filter by model and year lookup.
| Model / system | Years | Listed by |
|---|---|---|
| Dimension One spas with the Crystal Pure water management system | not given | Hot Tub Outpost OEM listing |
Check the cartridge you removed
Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Number formats: how Filbur, Unicel and Pleatco numbers compare.
Other Dimension One Spas cartridges
- 4CH-940 cartridge (OEM 1561-13), 4-5/8" (117 mm) × 15" (381 mm)
- 4CH-50 cartridge (OEM 1561-05), 4-5/8" (117 mm) × 14-3/4" (375 mm)
- C-4340 cartridge (OEM 1561-03), 4-15/16" (125 mm) × 11-5/8" (295 mm)
- 7CH-752 cartridge (OEM 1561-02), 7" (178 mm) × 14-3/4" (375 mm)
- 4CH-950 cartridge (OEM 1561-04), 4-5/8" (117 mm) × 12" (305 mm)
- 4CH-30 cartridge (OEM 1561-14), 4-5/8" (117 mm) × 11-7/8" (302 mm)
All 12 Dimension One Spas spa filters
Every number on this row, on one screen: cross-reference lookup. Published clean and replace intervals for this cartridge, and a buy link for the numbers above: replacement schedule and reorder. The interval comparison by brand: calculator.
Cleaner and test strips
Hose rinse and soak steps are in how to clean a cartridge. Named cleaners and strips are in filter cleaners and test strips.
Filter cleaner and test strips
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Leisure Time O Filter Clean Cartridge Cleaner Listing title: cartridge cleaner, 32 fl oz.
-
SpaGuard Filter Cleaner Listing title: filter cleaner for spas and hot tubs, 1 quart.
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AquaChek SPA 6-in-1 Test Strips Listing title: reads total bromine, total chlorine, free chlorine, pH, total alkalinity and total hardness.
Unicel C-5404 Listing we opened and checked. Match the diameter, length and both fittings on this page before you order. The price is on Amazon; we do not print one.
Sources
- Unicel 2026 Replacement Guide: OEM cross reference (Dimension One Spas section), PDF p.34 (printed p.30); spec table PDF p.11 (printed p.7) (PDF)
- Filbur Catalog & Reference Guide: Product by Pool/Spa Manufacturer (OEM), Dimension One Spas, printed p.33 (PDF p.17) (PDF)
- Hot Tub Outpost (retailer OEM listing): 1561-09: 5.5" x 17", 1-15/16" open top with 12 concentric holes, 2-7/8" open bottom; all spas with the Crystal Pure water management system; replaces Unicel C-5404, Filbur FC-3097, Pleatco PDO40-4 (web page)