Unicel 4CH-20 Replacement Filter Cartridge | 20 sq. ft. | 1-1/2" MPT Bottom

The Unicel 4000 Series 4CH-20 is a 20 sq. ft. replacement filter cartridge built for top-load spa skimmer systems. Its 1-1/2" male-threaded (MPT) bottom connection makes it a direct-thread replacement for a wide range of spa filter housings — no adapter required in most applications. With 204 precision-pleated panels of 3 oz. Reemay 2033 spunbond polyester media, this cartridge delivers consistent filtration performance and extended media life.

⚠️ IMPORTANT: Adapter Compatibility Note
This cartridge can also replace open-ended filters with a 1.9" inside diameter when used with a threaded adapter (sold separately). If your existing filter did not use a threaded connection, verify adapter requirements before ordering.

⚠️ IMPORTANT: Vita Spas Installation Note
On Vita Spa models that use a pad adapter in the skimmer: remove that adapter before threading the 4CH-20's 1-1/2" MPT connection directly into the suction fitting. Consult your spa manual if you are unsure whether your model uses this adapter.

Specifications

Filter Area	20 sq. ft.
Length	6 3/4"
Outer Diameter	4 5/8"
Top Inner Diameter	N/A
Bottom Inner Diameter	N/A
Material	3 oz. Reemay 2033
Pleat Count	204
Top Cap: molded cone handle	Bottom Cap: 1-1/2" male thread/MPT

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