How to Measure your Hot Tub Filter

Diagram of how to measure your hot tub filter.

Use these instructions to measure your hot tub filter.

  1. Measure the outside diameter of the cartridge (in inches, +/- 1/32").
     
  2. Measure the cartridge length including end caps, but excluding any handles or other extensions. Measure through the centre if possible (in inches, +/- 1/16").
     
  3. Use the Filter End Cap Chart to identify your cartridge end cap configuration. If the top and/or bottom is "open," measure the inside diameter (in inches, +/- 1/32").