Hydropool replacement X18-PHY Filters used in the Serenity hot tubs from 2022-2022. Serenity hot tubs require 2 of these filters to complete the filtering system. These filters have replaced the Serenity New Wave filters that where collapsing. Some of these models require the sleeve adaptors Hydropool P/N 5005045.
Replaces Pleatco X18-PHY25, Hydropool 4520036