Dimension One Spas OEM 1561-12 spa filter (7CH-975)

Dimension One Spas (1-1/2" SAE thread)

Replacement numbers

Unicel 7CH-975, Pleatco PDO75P3

Fits Dimension One Spas OEM 1561-12.

Diameter 7" (178 mm)Length 10-1/2" (267 mm)75 sq ft2 models listed

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Unicel7CH-975
PleatcoPDO75P3 (as printed in the Filbur catalog Dimension One Spas section (printed p.33); not found in the Pleatco 2023 Unicel cross reference)
FilburFC-0475
Topsemi-circular handle
Bottom1-1/2" SAE thread
Ø 7" (178 mm)10-1/2" (267 mm)Side view · end views belowTopBottom
Top: semi-circular handle
Bottom: 1-1/2" SAE thread
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 75 sq ft media.

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Dimension One Spas files this cartridge as 7CH-975 cartridge (OEM 1561-12), in the Dimension One Spas (1-1/2" SAE thread) group. Numbers on the row: OEM 1561-12; Unicel 7CH-975; Pleatco PDO75P3; Filbur FC-0475. 7" across, 10-1/2" long, top semi-circular handle, bottom 1-1/2" SAE thread, 75 sq ft.

PDO75P3 is the Pleatco string Filbur prints next to 7CH-975 (OEM 1561-12) on printed p.33. PDO75P3 itself is absent from Pleatco’s 2023 Unicel cross-reference.

Dimension One Spas applications recorded for this cartridge: Dimension One Madrid, Barcelona, years 1996–2000, listed by Hot Tub Outpost OEM listing; @Home hot tubs (all), years 2000, listed by Hot Tub Outpost OEM listing.

Hold 7CH-975 next to 7CH-552 differs by Unicel 7CH-552, no Pleatco number, no Filbur number, bottom 2” male thread/MPT, 52 sq ft, OEM 1561-10, note says Unicel's Dimension One cross reference rates 1561-10 / 7CH-552 at 75 sq ft, but Unicel's own spec table rates 7CH-552 at 52 sq ft (7" x 10-1/2", 2" MPT, semi-circular handle), and both retailer listings (Hot Tub Outpost and SpaStore) give 52 sq ft at 7" x 10-1/2" with a 2" MPT bottom; 52 is shown. Both retailers name Pleatco PTL55XW-F2M and Filbur FC-0465 as equivalents, but the Pleatco 2023 catalog lists PTL55XW-F2M among its deactivated part numbers with no replacement (PDF p.24) and the Filbur catalog does not list FC-0465, so neither is shown as a current equivalent. Hot Tub Outpost lists the 1994 Arena and Diamante under this part, while its 01561-03 listing also names the 1994 Arena and Diamante; check the old cartridge.; C-7367 differs by Unicel C-7367, Pleatco PDO75-2000, Filbur FC-3059, 7-1/8" diameter, top closed w/ Y stand-offs, bottom 2" / open w/ twist lock, OEM 1561-00, note says Unicel and Filbur both flag this for Dimension One 75 models dated after 2000. Pleatco prints the size as 7-1/4" x 10-5/8" (castle top, open with twist lock) against Unicel's 7-1/8" x 10-1/2"..

Pages checked for 1561-12: Unicel 2026 Replacement Guide on 7CH-975 (OEM cross reference (Dimension One Spas section), PDF p.33 (printed p.29); spec table PDF p.15 (printed p.11)). Filbur Catalog & Reference Guide on 7CH-975 (Product by Pool/Spa Manufacturer (OEM), Dimension One Spas, printed p.33 (PDF p.17)). Hot Tub Outpost (retailer OEM listing) on 7CH-975 (01561-12: 7" x 10-5/8", handle, 1-1/2" SAE coarse thread, 75 sq ft; 1996–2000 Madrid and Barcelona, all 2000 model-year @Home hot tubs).

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 Madrid, Barcelona1996–2000Hot Tub Outpost OEM listing
@Home hot tubs (all)2000Hot 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.

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All 12 Dimension One Spas spa filters

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Cleaner and test strips

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