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Home › Hot Spring › 4CH-35 cartridge (OEM 31382)

Hot Spring OEM 31382 spa filter (4CH-35)

Listed for: Hot Spring (Watkins) — unverified

Your replacement
Unicel 4CH-35

Fits Hot Spring OEM 31382 (formerly 31116) unverified

Ø 4-5/8"L 16"35 sq ft
Unicel4CH-35
Pleatconot found in source
Filburnot sourced
Topmolded cone handle
Bottom1-1/2” male thread/MPT
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Retailer search links — see disclosure. Verify dimensions before ordering.

Ø 4-5/8" 16" Top: molded cone handle Bottom: 1-1/2” male thread/MPT
Diagram drawn to scale from catalog dimensions · 35 sq ft media

How to confirm this is your filter

Pull your current cartridge and measure it end to end, including any handle, and across the widest point of the pleats. This cartridge measures 4-5/8" in diameter and 16" long, with a molded cone handle on top and a 1-1/2” male thread/MPT on the bottom. The bottom fitting matters most: a cartridge with the right diameter but the wrong thread or open-end size will not seal in the filter housing, letting unfiltered water bypass the media.

The 35 sq ft rating describes the pleated media area. Hot Spring housings are designed around a particular cartridge, so choose a replacement with the same size and fittings rather than a larger area rating. We did not find a Pleatco equivalent for 4CH-35 in the Pleatco 2023 cross-reference, so search by the Unicel or OEM number.

⚠ Unverified / possible conflict: this row has not been fully confirmed against a second source. Gaps: no Pleatco equivalent found in Pleatco 2023 xref p.43; no Filbur equivalent sourced; no model-year range in source. Measure your old cartridge before ordering.

Sources