Cold Plunge Filter CartridgeMaintaining your ReGen Cold Tub is a breeze, however, the most important aspect is maintaining a clean cold plunge filter! Your tub will arrive with a brand new filter, however, it is recommended to have spares on hand! ReGen's OG Cold Tub filter should last, on average, 6 weeks (in a residential setting). A 6 month supply will come with 4 filters; a 12 month supply will come with 8 filters. The Blast filter should last, on average, 8 weeks (in a