When to replace a hot tub filter

Short answer

About once a year for a standard pleated cartridge, per Master Spas, and every 18 months for Sundance's pleated filter; fine inner inserts go every 6 months. Replace sooner when cleaning no longer restores flow or the pleats break down.

Updated October 2026By the HotTubFinder research desk

Cleaning a hot tub filter: turn the tub off, lift the filter out, hose each pleat top down, soak it in filter cleaner, rinse and put it back; no brushes — The routine between replacements.

How often each maker says to replace the filter and clean the filter

6 makers

When six makers say to replace and clean hot tub filters
Maker	Replace the filter	Clean the filter
Bullfrog X Series	When worn after multiple cleanings	Every 3 to 6 weeks
Caldera	Not given as a fixed interval	Monthly
Hot Spring	Not given as a fixed interval	Monthly
Jacuzzi	When cleaning no longer restores it	Monthly
Master Spas	Standard cartridge about 1 year; EcoPur insert 6 months	At least monthly
Sundance	Pleated filter 18 months; inner insert 6 months	Monthly

From each maker's current owner's manual, makers A to Z. Checked October 2026.

How do you know a hot tub filter needs replacing?

When cleaning stops working. Master Spas says to replace a cartridge when cleaning no longer improves filtration or the pleats start to deteriorate. Bullfrog says worn cartridges need replacing after multiple cleanings. Keep the date you fitted each cartridge, so you can match it against your maker's interval.

Why do some hot tub filters have to be thrown away?

Some are built as disposable parts. Sundance's 880 manual says its MicroClean cartridge is designed to be thrown away, and that reusing it can release trapped particles back into the water. Master Spas replaces its EcoPur insert every 6 months. Sundance and Jacuzzi controls can show a reminder when one is due.

Which replacement filter fits my hot tub?

The one your maker specifies. Bullfrog says to use only its own replacement cartridges to keep warranty protection. Your tub's filter area and count are in our gallons and filter size table; across 227 spec sheets that list it, the median is 50 square feet. For what filter size means when buying, see hot tub filters. CDC's hot tub guidance also calls for regular cartridge replacement on the maker's schedule.

Common questions

How often should you replace a hot tub filter?

About every 12 months for a standard pleated cartridge (Master Spas), 18 months for Sundance's pleated filter, and every 6 months for fine inner inserts.