Cal Spas OEM FIL11700016 spa filter (6CH-975)

Cal Spas Unverified: no Pleatco equivalent in Pleatco 2023 cross reference; no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources Checked 2026-11-03: ezhottubparts still crosses FIL11700016 to Unicel 6CH-960 (52 sq ft); a Spa Parts Warehouse listing for FIL75-7D155H2MCT-3 / FIL11700016 gives 75 sq ft, 7" x 15", 2" MPT, which matches 6CH-975's area but neither catalog's thread wording. Checked 2026-11-04: Unicel's Cal Spas section still prints FIL11700016 as 6CH-975 (6-3/4" x 15-1/2", 2" SAE, 75 sq ft). A search of the Filbur catalog the same day found no FIL11700016. Unresolved. Checked 2026-11-06: Unicel PDF p.30 (printed p.26) still prints FIL11700016 as 6CH-975, 6-3/4" x 15-1/2", 2" SAE, 75 sq ft. No new manufacturer model chart and no Filbur row for FIL11700016. Checked 2026-11-07: Unicel’s Cal Spas line still prints FIL11700016 as 6CH-975, 6-3/4" × 15-1/2", 2" SAE, 75 sq ft. No model-to-cartridge chart was found. Still unresolved. Checked 2026-11-08: Unicel PDF p.30 still prints FIL11700016 as 6CH-975, 6-3/4" x 15-1/2", 2" SAE, 75 sq ft. A text search of the Pleatco 2023 PDF and the Filbur PDF found no 6CH-975 and no FIL11700016. Still unresolved.

Replacement numbers

Unicel 6CH-975

Fits Cal Spas OEM FIL11700016.

Diameter 6-3/4" (171 mm)Length 15-1/2" (394 mm)75 sq ft

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Unicel6CH-975
Pleatconot found in source
Filburnot found in Filbur catalog
Topsemi-circular handle
Bottom2" SAE thread
Ø 6-3/4" (171 mm)15-1/2" (394 mm)Side view · end views belowTopBottom
Top: semi-circular handle
Bottom: 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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Cal Spas is the group name on the Cal Spas row 6CH-975 cartridge (OEM FIL11700016). Match these numbers: OEM FIL11700016; Unicel 6CH-975. 6-3/4" across, 15-1/2" long, top semi-circular handle, bottom 2" SAE thread, 75 sq ft.

6CH-975 is easy to confuse on the Cal Spas table. C-5374 differs by Unicel C-5374, Pleatco PLBS75, Filbur FC-2971, 5-5/16" diameter, 14-13/16" long, top 2-1/8" / open, bottom 2-1/8" / open, no OEM number, note says Filbur lists its FC-2971 equivalent at 5-5/16" x 14-11/16", 65 sq ft. 5CH-752 differs by Unicel 5CH-752, Pleatco PCAL60-F2M, Filbur FC-0202, 5-3/16" diameter, 16-1/8" long, top bar handle, bottom 2” male thread/MPT, no OEM number, note says Leisure Time Inc. lists Cal Spas OEM 50753 for 5CH-752 (single retailer source, not shown as OEM). Filbur's catalog prints the Unicel number beside FC-0202 as "5CH-702".

Pleatco and Filbur do not have a number on this row. Search FIL11700016 or the Cal Spas part you pulled out of the spa.

Left blank on purpose: no Pleatco equivalent in Pleatco 2023 cross reference; no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources Checked 2026-11-03: ezhottubparts still crosses FIL11700016 to Unicel 6CH-960 (52 sq ft); a Spa Parts Warehouse listing for FIL75-7D155H2MCT-3 / FIL11700016 gives 75 sq ft, 7" x 15", 2" MPT, which matches 6CH-975's area but neither catalog's thread wording. Checked 2026-11-04: Unicel's Cal Spas section still prints FIL11700016 as 6CH-975 (6-3/4" x 15-1/2", 2" SAE, 75 sq ft). A search of the Filbur catalog the same day found no FIL11700016. Unresolved. Checked 2026-11-06: Unicel PDF p.30 (printed p.26) still prints FIL11700016 as 6CH-975, 6-3/4" x 15-1/2", 2" SAE, 75 sq ft. No new manufacturer model chart and no Filbur row for FIL11700016. Checked 2026-11-07: Unicel’s Cal Spas line still prints FIL11700016 as 6CH-975, 6-3/4" × 15-1/2", 2" SAE, 75 sq ft. No model-to-cartridge chart was found. Still unresolved. Checked 2026-11-08: Unicel PDF p.30 still prints FIL11700016 as 6CH-975, 6-3/4" x 15-1/2", 2" SAE, 75 sq ft. A text search of the Pleatco 2023 PDF and the Filbur PDF found no 6CH-975 and no FIL11700016. Still unresolved..

Where those figures are printed: Unicel 2026 Replacement Guide on 6CH-975 (OEM cross reference (Cal Spas section), PDF p.30 (printed p.26); spec table PDF p.13 (printed p.9)). Spa Parts Warehouse (retailer listing) on 6CH-975 (Replacement for FIL75-7D155H2MCT-3 / FIL11700016 (fetched via search 2026-11-03): 7" diameter, 15" length, 2" MPT, 75 sq ft).

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 Cal Spas cartridges

All 9 Cal 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

Unverified. This row has not been fully confirmed against a second source. Gaps: no Pleatco equivalent in Pleatco 2023 cross reference; no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources Checked 2026-11-03: ezhottubparts still crosses FIL11700016 to Unicel 6CH-960 (52 sq ft); a Spa Parts Warehouse listing for FIL75-7D155H2MCT-3 / FIL11700016 gives 75 sq ft, 7" x 15", 2" MPT, which matches 6CH-975's area but neither catalog's thread wording. Checked 2026-11-04: Unicel's Cal Spas section still prints FIL11700016 as 6CH-975 (6-3/4" x 15-1/2", 2" SAE, 75 sq ft). A search of the Filbur catalog the same day found no FIL11700016. Unresolved. Checked 2026-11-06: Unicel PDF p.30 (printed p.26) still prints FIL11700016 as 6CH-975, 6-3/4" x 15-1/2", 2" SAE, 75 sq ft. No new manufacturer model chart and no Filbur row for FIL11700016. Checked 2026-11-07: Unicel’s Cal Spas line still prints FIL11700016 as 6CH-975, 6-3/4" × 15-1/2", 2" SAE, 75 sq ft. No model-to-cartridge chart was found. Still unresolved. Checked 2026-11-08: Unicel PDF p.30 still prints FIL11700016 as 6CH-975, 6-3/4" x 15-1/2", 2" SAE, 75 sq ft. A text search of the Pleatco 2023 PDF and the Filbur PDF found no 6CH-975 and no FIL11700016. Still unresolved.. Measure your old cartridge before ordering.

Sources