Clarathon Premium Hot Tub Filters

    Drop-in & screw-in spa filter cartridges

    Measure Your Old Hot Tub Filter

    Use Menu to Narrow Your Search:

    1. Choose Type: Drop-In or Screw-In.
    2. Got Part #? [Search this category] No match? Go to 3.
    3. Pick: Spa Brand if known. No match? CLEAR Brand (x). Go to 4.
    4. Select: Diameter & Length ranges to narrow selection.

    Follow measuring tips below:

    Measuring tips: tape measure showing fractional increments

    Confirm Spa Filter Dimensions

    • Round all figures to nearest ⅛”.
    • Compare to search results.
    • View photos to confirm match.
    • Variances ±⅛” are normally OK.

    See how to measure filter below:

    Measuring spa filter cartridge diameter & length

    How-to Measure Diameter & Length

    Measure old filter’s end-cap Diameter (edge-to-edge width) & Length (cap-to-cap height). Exclude handles/fittings.

    Measuring spa filter cartridge openings

    How-to Measure Inner Opening

    If filter has flush end-cap opening(s), measure Inside Diameter.

    Measuring spa filter cartridge fittings

    How-to Measure External Fitting

    If filter has a protruding fitting, measure Outside Diameter. Note style: Coarse Thread, Fine Thread, or Male Slip.