Unicel 4000 Series 19 sq. ft. Replacement Filter Cartridge | 4CH-21 Pool Lighting After initial dose

After initial dose

Full-size water ring

Excel Filters: XLS-718

SM & SMBW 4000 Series pool and spa DE filters

Unicel 4000 Series 19 sq. ft. Replacement Filter Cartridge | 4CH-21 Pool Lighting After initial doseThe Unicel 4CH 21 is a 4000 Series 19 sq. ft. replacement filter cartridge engineered for top load spa and hot tub filtration systems with a 1 1 2" MPT threaded suction connection. With 158 pleats of 3 oz. Reemay 2033 polyester media, this cartridge delivers consistent particle capture and reliable water clarity in compact spa filter housings. The molded cone handle on top simplifies removal at service time, while the 1 1 2" male pipe thread bottom