TETRA UV-MINI REPLACEMENT Quartz Sleeve ( MINI ) ** Manufacturer recommendation is to service your filter once every year to year and a half ( 12 - 18 months ) Service PLS5 Tetra Greenfree UV-MINI Brand NEW in the BOX INCLUDES: ONE - TETRA UV-MINI REPLACEMENT Quartz Sleeve ( MINI ) A UV Filter will lose its effectiveness if you do not regularly service the components. This can result in green pond !