Clarathon Premium Hot Tub Filters

    Measuring spa filter cartridge diameter & length

    Measure Diameter & Length

    Note your old filter’s end cap Diameter (edge-to-edge) and Length (cap-to-cap) rounded to nearest ⅛". Exclude any handles/fittings. Measure any openings or fittings per info below.

    Measuring spa filter cartridge openings

    Measure Opening Diameter

    Drop-In filters often have 2 open ends, or just 1 with closed top. A few Screw-In filters have inner threads with handle top. Measure inside diameter of opening(s). Match to listing specifications.  

    Measuring spa filter cartridge fittings

    Measure Fitting Outside Diameter (OD)

    If your filter has a fitting, note the style (Coarse Thread, Fine Thread or Male Slip) and determine OD. Match to listing specifications. Refer to photos.  

    Drop-in & screw-in spa filter cartridges

    Use Menu to Narrow Filter Selection

    Noting old filter's dimensions:

    1. Choose Type: Drop-In or Screw-In.
    2. Got Part #? Try: [Search these products]. No match? Go to 3.
    3. Pick: Spa Brand, if known. No match? CLEAR Brand (x). Go to 4.
    4. Select: Diameter & Length ranges. Dimensions may vary ± ⅛".