Hot Tub Filter Cleaning: How Often and How to Do It Right
Rinse your hot tub filter weekly with a garden hose. Deep-clean monthly with an overnight soak in filter cleaner. Acid wash only when mineral scale is visible, it is not a routine step. Replace standard cartridge filters every 1-2 years, or every 6 months for EcoPur-style media filters. Never run the pump without a filter installed. Return to our hot tub maintenance guide for the full scope of spa upkeep.
According to CDC hot tub water quality guidelines{:target=“_blank”}, proper filtration is a critical layer of spa sanitation, sanitizer alone cannot compensate for a clogged filter. Dirty filters are one of the most common causes of cloudy water, and replacing a filter often resolves chemistry problems that chemical adjustments cannot.
Video guide
Video: “HOT TUB MAINTENANCE For Beginners” by Swim University
What You Need Before You Start
Gather these before removing the filter:
- Garden hose with adjustable nozzle, a standard garden hose does the job; no pressure washer (high pressure destroys the pleats)
- Bucket or trash can large enough to submerge the filter, a 5-gallon bucket works for smaller cartridges; a 20-gallon trash can for larger filters
- Filter cleaning solution or automatic dishwasher detergent, either works for the soak step; commercial filter cleaner is formulated for the job
- Muriatic acid, only needed for the acid wash step; not a routine supply
- Rubber gloves and eye protection, required for the acid wash only
- Spare cartridge (recommended), rotating two filters is one of the most practical things you can do to extend total filter life
How Often Should You Clean a Hot Tub Filter?
| Task | Frequency | Method |
|---|---|---|
| Quick rinse | Weekly | Garden hose, 2-3 minutes |
| Deep soak | Monthly | Overnight in filter cleaner solution |
| Acid wash | Only when scale is visible | After degreasing, not routine |
| Replace cartridge | Every 1-2 years | When pleats show physical damage |
| EcoPur-style filter | Replace every 6 months | Do NOT clean chemically |
PSI-based trigger: Establish your pressure gauge baseline right after installing a fresh, clean filter. When pressure climbs 8-10 PSI above that baseline, it is time to clean. For heavy-use spas, that may happen sooner than the weekly schedule suggests. For lightly used spas, monthly cleaning may be sufficient.
Cartridge lifespan varies: with proper cleaning at every interval, SwimUniversity data puts filter life at 3-5 years. In practice, most filters need replacement every 1-3 years. The key variable is how consistently you do the deep soak, filters that only get rinsed wear out faster.
Step-by-step: weekly rinse (5 minutes)
- Turn off the hot tub pump, never remove the filter while the pump is running
- Remove the filter cartridge from the housing, rotate counterclockwise on most models; check your manual if it does not come free easily
- Spray off with a garden hose at a 45-degree angle, top to bottom, work from the top of each pleat downward
- Work between the pleats, direct the stream into the gaps; do not fold or compress the pleats
- Inspect for damage, check for torn pleats, cracked end caps, and worn O-rings while the cartridge is out; replace O-rings if they show cracking
- Reinstall the cartridge and restore power, make sure the cartridge seats fully in the housing before starting the pump
Do not use a pressure washer. High-pressure spray tears the filter media and collapses the pleats, reducing filtration area. Even a pressure washer on low setting does more harm than a garden hose.
Step-by-step: monthly deep soak
The deep soak is the step most guides underexplain, and it is the step that actually restores filter efficiency. A garden hose rinse removes loose debris but leaves body oils embedded in the pleats. Those oils become a breeding ground for bacteria and clog filtration pores over time.
- Remove filter cartridge (pump off first)
- Rinse off loose debris with a garden hose, same 45-degree technique as the weekly rinse
- Mix soak solution: 1 cup automatic dishwasher detergent (or commercial filter cleaner) per 5 gallons of water
- Submerge the filter completely, weight it down with a rock or a brick if it floats
- Soak overnight (8 hours minimum, longer is better; 12-24 hours is fine)
- Remove and rinse thoroughly, run the hose until the water runs completely clear with no suds
- Reinstall or allow to dry completely, if you are rotating two cartridges, let this one dry before storing it as your rotation spare
After completing the deep soak, we recommend shocking your hot tub after a deep clean. Reinstalling a clean filter stirs up the water and is a good time to refresh the sanitizer level.
Acid wash: only when you see scale
Acid washing is for mineral deposits, the white, crusty buildup that forms when calcium hardness or pH drifts high. It is not a routine maintenance step. If your filter cleans up fine with the monthly soak, you do not need to acid wash.
Signs you need an acid wash:
- White or gray crusty deposits that do not rinse off
- Rough texture on the pleats that was not there before
- Calcium scale buildup visible on the shell or jets (same chemistry affecting the filter)
How to do it safely:
- Degrease first, complete the full overnight soak before acid washing. Oils cement to the filter surface during acid contact and become permanent if you skip degreasing.
- Mix ratio: 1 part muriatic acid to 20 parts water, always add acid to water, never reverse the order
- Submerge the filter and soak until bubbling stops (about 20 minutes)
- Rinse thoroughly with multiple passes of clean water
- Neutralize any spills with baking soda
Safety during acid wash: rubber gloves, eye protection, outdoor location, and good ventilation are not optional. Keep baking soda nearby to neutralize spills. Per SwimUniversity data, never acid wash without degreasing first, the acid locks oils permanently into the filter media if organics are still present.
Special case: EcoPur and proprietary media filters
Some hot tubs use a multi-stage filtration system with a secondary media filter alongside the standard cartridge. Master Spas’ EcoPur Charge filter is the most common example. According to the Master Spas filter maintenance guide{:target=“_blank”}, these filters:
- Cannot be cleaned with chemical filter cleaner, the cleaning chemicals damage the filter media
- Must be replaced every 6 months regardless of appearance
- Are identifiable by an orange or colored collar on the filter housing
If your hot tub has a secondary filter with a colored collar, do not apply the standard cleaning protocol to it. Replace it on schedule and follow your owner’s manual for the cartridge cleaning only. Keeping a spare EcoPur filter on hand means you never have to run the spa without one while waiting for a replacement to ship. If you are winterizing your filter, remove and dispose of the EcoPur filter before storage and install a fresh one at startup.
When to Replace Instead of Clean
Cleaning can only do so much. Replace the cartridge when you see any of these:
- Torn or frayed pleats, physical damage reduces filtration surface area and cannot be reversed by cleaning
- End caps cracked or separating, the filter will bypass water around the media instead of through it
- Filter will not come clean even after a full overnight soak (the oils are set permanently)
- Pressure climbs back to the cleaning threshold within 48 hours of a fresh clean, the filter media is exhausted
- Visible discoloration that does not rinse out (tan or brown staining of the pleats)
We recommend planning to replace annually as a baseline and inspecting at every cleaning. The SwimUniversity 3-5 year lifespan assumes perfect maintenance at every interval. Realistically, expect 1-2 years for a filter that is rinsed weekly and soaked monthly.
Rotation tip: We find that keeping two cartridges and swapping them each cleaning cycle is one of the most effective longevity strategies. The filter you remove gets cleaned and dried while the fresh one goes in. Dry cartridges last significantly longer than wet ones, and you always have a clean filter ready, which matters when you have guests arriving and a dirty filter.
Frequently asked questions
Can I clean my hot tub filter with bleach?
No. Bleach damages the filter media and breaks down the bonding materials in the pleats. Use a dedicated filter cleaning solution or automatic dishwasher detergent for the soak. The NSF spa water quality standards{:target=“_blank”} outline why filter integrity matters, damaged media allows fine particles through that a healthy filter would capture.
How long does a hot tub filter last?
Plan for 1-3 years with routine cleaning. Filters maintained with regular weekly rinses and monthly soak cycles can last up to 5 years per SwimUniversity data, but that assumes consistent care at every interval. A filter that only gets rinsed (no soak) may need replacement within a year. Replace when pleats show physical damage regardless of age.
Can I run a hot tub without a filter?
Never. Running the pump without a filter installed draws debris directly into the impeller and can damage the pump within hours. Keep a spare cartridge specifically to avoid this situation, if your filter is soaking overnight, the spare goes in. Pool filter cleaning steps follow the same principle for pool cartridge filter cleaning: never run without filtration.
Why does my hot tub get cloudy right after I clean the filter?
The cleaning process loosens debris that is still suspended in the water. Run the pump for 30-60 minutes after reinstalling a clean filter, the cloudiness should clear as the water passes through the clean media. If it does not clear within an hour, the issue is chemistry-related, not the filter.
How do I know what size filter cartridge I need?
Check your owner’s manual first, it lists the part number. If you do not have the manual, measure the old cartridge: diameter at the top and overall length are the two sizing specs. The part number is often printed on the end cap of the cartridge itself. When in doubt, bring the old cartridge to the pool supply store for a match.
For pool filter cleaning steps on swimming pool cartridge systems, see our dedicated pool filter guide.