Dimension One Spas OEM 1561-14 spa filter (4CH-30)

Dimension One Spas

Replacement numbers

Unicel 4CH-30, Pleatco PTL25P-4

Fits Dimension One Spas OEM 1561-14.

Diameter 4-5/8" (117 mm)Length 11-7/8" (302 mm)25 sq ft3 models listed

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Unicel4CH-30
PleatcoPTL25P-4 (as printed in the Filbur catalog Dimension One Spas section (printed p.33); not found in the Pleatco 2023 Unicel cross reference)
FilburFC-0141
Topmolded cone handle
Bottom1-1/2” male thread/MPT
Ø 4-5/8" (117 mm)11-7/8" (302 mm)Side view · end views belowTopBottom
Top: molded cone handle
Bottom: 1-1/2” male thread/MPT
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 25 sq ft media.

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For Dimension One Spas, 4CH-30 cartridge (OEM 1561-14) sits in Dimension One Spas. The cross-reference prints OEM 1561-14; Unicel 4CH-30; Pleatco PTL25P-4; Filbur FC-0141. 4-5/8" across, 11-7/8" long, top molded cone handle, bottom 1-1/2” male thread/MPT, 25 sq ft.

Catalog note for 1561-14: Unicel's spec table rates 4CH-30 at 30 sq ft (4 oz media); its OEM cross reference and Filbur both give 25 sq ft for the Dimension One part, which is the figure shown.

PTL25P-4 is the Pleatco string Filbur prints next to 4CH-30 (OEM 1561-14) on printed p.33. PTL25P-4 itself is absent from Pleatco’s 2023 Unicel cross-reference.

Model list attached to 4CH-30 cartridge (OEM 1561-14): Dimension One Legend, years 1996, listed by Hot Tub Outpost OEM listing; Dimension One SRX, Impulse, Duet, years 1991 and 1993, listed by Hot Tub Outpost OEM listing; Dimension One Little Dipper, years 1994–1995, listed by Hot Tub Outpost OEM listing.

4CH-30 is easy to confuse on the Dimension One Spas table. 4CH-950 differs by Unicel 4CH-950, Pleatco PDO-UF25P2, Filbur FC-0173, 12" long, top semi-circular handle, bottom 1-1/4" SAE thread, OEM 1561-04, note says Unicel gives the length as 12"; Filbur's table prints 11-7/8" (and "4-5/8 x 12" in its description) for FC-0173.. C-4340 differs by Unicel C-4340, Pleatco PMT40, Filbur FC-3081, 4-15/16" diameter, 11-5/8" long, top 2-1/8" / open, bottom 2-1/8" / open, 40 sq ft, OEM 1561-03, note says Discontinued by Dimension One Spas (noted in both the Unicel guide and the Filbur catalog); the replacement cartridge is still made..

Source locations for this Dimension One Spas row: Unicel 2026 Replacement Guide on 4CH-30 (OEM cross reference (Dimension One Spas section), PDF p.33 (printed p.29); spec table PDF p.7 (printed p.3)). Filbur Catalog & Reference Guide on 4CH-30 (Product by Pool/Spa Manufacturer (OEM), Dimension One Spas, printed p.33 (PDF p.17)). Hot Tub Outpost (retailer OEM listing) on 4CH-30 (01561-14: 4-3/4" OD x 11-7/8", handle, 1-1/2" MPT fine thread; 1996 Legend, 1991 and 1993 SRX/Impulse/Duet, 1994–1995 Little Dipper; replaces Unicel 4CH-30, Filbur FC-0141, Pleatco PTL25P-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 / systemYearsListed by
Dimension One Legend1996Hot Tub Outpost OEM listing
Dimension One SRX, Impulse, Duet1991 and 1993Hot Tub Outpost OEM listing
Dimension One Little Dipper1994–1995Hot 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.

The same 4CH-30 number is also on the Sundance, Freedom Spas, Saratoga Spas pages.

Other Dimension One Spas cartridges

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

Sources