Filter Measurement Tips

Hot Tub Filter Measurement

The Diameter (width) of your hot tub filter cartridge is measured from one outside edge to the other outside edge at the widest part of the filter. Measure the diameter down to the nearest 1/16".

Hot Tub Filter Measurement

The Length of your hot tub filter is measured from the outside edge of one end cap to the outside edge of the other end cap.


Hot Tub Filter Measurement

In open end hot tub filters (type 1), you can measure the hole diameter(s). Don't include any tapering or pinholes in your measurements.


Hot Tub Filter Measurement

With slotted hole end caps, measure the diameter of the hole without the slots. Most slotted holes are 1 7/8" or 2 3/8" in diameter.


Important Note: While you should take these measurements as accurately as possible, you can also take them with a grain of salt. The measurements on old hot tub filters may not match the new filter measurements on Find-My-Filter due to expansion, contraction and wear of the old one. You could easily be off by 1/16th to 1/8th inch. Be prepared to adjust your Find-My-Filter measurement input slightly if you aren't getting a listing that looks right to you.

There are two types of threaded ends skinny (normal) and fat (SAE). If your filter has a threaded end, be sure to take note of which kind you have.

Hot Tub Filter MeasurementHot Tub Filter Measurement

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