How to clean a hot tub filter (and when to replace it)

To clean a hot tub filter, turn off power at the breaker, pull the cartridge, and hose between every pleat from top to bottom. Do that every 1 to 2 weeks. Once a month, soak it in a spa filter cleaner per the label, then rinse until the water runs clear. Replace the cartridge every 12 to 24 months.

Why it matters

All the water in the tub passes through the filter many times a day. A clogged filter slows the flow, and low flow is the number one cause of heater shutdowns and error codes such as FLO and HTR FLOW LOSS. A dirty filter also uses up sanitizer and makes water cloudy.

Cleaning schedule

How often	What to do	Time
Every 1–2 weeks	Hose rinse	5 minutes
Monthly	Filter cleaner spray or soak, then rinse	15 minutes plus soak time
Every 3–4 months (at each water change)	Overnight chemical soak	Overnight
Every 12–24 months	Replace the cartridge	5 minutes

Heavy use, several bathers, or lots of lotion and sunscreen means cleaning more often.

Weekly rinse, step by step

1. Turn off the tub at the breaker. You do not want the pump to start with the filter out and pull debris in.
2. Remove the filter. Most lift out or unscrew counterclockwise from the filter compartment. Some have a retaining ring or basket.
3. Rinse with a garden hose. Work top to bottom at a 45-degree angle. Spread the pleats with your fingers and flush each one. Rotate until you have done the full circle.
4. Check the cartridge. Look for torn fabric, cracked end caps, or a collapsed core.
5. Reinstall and restore power. Make sure it is seated or threaded fully so water cannot bypass it.

Use normal hose pressure. A pressure washer tears the fabric and drives dirt deeper.

Monthly filter cleaner soak

A hose removes hair and grit. It does not remove body oils, lotion, or mineral scale, which is what actually blinds the fabric. For that you need a filter cleaner.

1. Rinse the filter first to remove loose debris.
2. Mix the filter cleaner with water in a clean bucket per the product label. Use a bucket kept only for this job.
3. Submerge the cartridge fully. Soak for the time on the label, from 1 hour to overnight depending on the product.
4. Rinse thoroughly until no suds or residue come out. Leftover cleaner causes foam.
5. Let it dry completely if you have time. Drying helps kill what the soak missed and lets the fibers recover.

Spray-on cleaners are quicker: spray, wait about 15 minutes, rinse. They suit the monthly clean. Save the full soak for water changes. Follow the product label and wear gloves and eye protection. Never mix filter cleaner with chlorine or any other chemical.

What not to use

• Dish soap or laundry detergent. They never fully rinse out, and the tub foams for weeks.
• Dishwasher. Heat warps the core and end caps.
• Pressure washer. Damages the pleats.
• Stiff brushes. They fuzz the fabric, which then clogs faster.
• Straight bleach. It does not cut oil and it breaks down the material.

When to replace the filter

Replace it if any of these are true:

• It is 12 to 24 months old. As a rough guide, a cartridge lasts about 10 to 15 chemical cleanings.
• The pleats are flattened, frayed, fuzzy, or torn.
• The fabric is still gray or brown after a soak.
• End caps are cracked or the center core is crushed.
• Flow errors return soon after a cleaning.
• The water stays cloudy even though the chemistry is right.

A quick test for a worn filter: if a flow error clears when you briefly run the tub with the filter removed, and comes back when you put the cleaned filter in, the cartridge is done.

To order the right one, you need its length, diameter, and end-cap style, or the part number printed on the end cap. See how to find the right replacement filter, or browse hot tub filters.

Keep two filters and rotate

The easiest routine is to own two cartridges. When one comes out for a soak, the clean dry spare goes straight in. The tub is never without a filter, each cartridge gets to dry fully between uses, and both last longer.

Other filter types

Some tubs use disposable filters, which are replaced every few months and not cleaned with chemicals, or ceramic and microfiber filters with their own cleaning rules. Check your owner's manual if your filter is not a standard pleated cartridge.

Make it automatic

Filter care is easy to forget because nothing looks wrong until the heater shuts off. Put the rinse, soak, and replacement dates on a calendar, or set them up with AskTub reminders. The full routine is in the hot tub maintenance schedule.