Clean Or Replace Hot Tub Filter Uk

Direct answer: clean the cartridge while the pleats still open, rinse clear and hold their shape. Replace it when pleats stay flattened, torn, slimy, heavily discoloured or when clean-looking water still turns cloudy because flow through the media is poor.

Hot Tub Geek lists practical replace triggers including compressed pleats, stubborn discolouration and poor clarity. Canadian Spa Company UK reminds owners that cleaner does not turn an end-of-life cartridge back into a new one, and Catalina Spas UK gives annual replacement as a general maintenance rule adjusted for use.

Decision tree

Damage visible? Torn bands, broken caps or crushed pleats mean replace.
Pleats still open? If they fan back out after rinsing and drying, cleaning may be enough.
Smell or slime remains? Replace rather than repeatedly soaking the same tired media.
Cloudiness returns after balancing? Treat the filter as a likely restriction and replace if cleaning has not restored flow.
No spare during a guest turnover? Stop cleaning and fit a known-good cartridge if the current one is failing.

How to clean when cleaning is still sensible

Rinse from top to bottom between the pleats, soak with a dedicated filter cleaner according to the product instructions, rinse again, then let the cartridge dry fully before reinstalling. Avoid dish soap, harsh household cleaners and pressure washing; the aim is to clear the media, not strip or tear it.

Stop conditions

Stop trying to rescue the cartridge if it never rinses clear, dries stiff and collapsed, smells musty after cleaning, or produces weak flow as soon as it goes back in. At that point, more cleaning time is not disciplined maintenance; it is delaying a replacement that the spa is already asking for.

Keep the decision low-stress

One known-good spare keeps the decision rational. You can soak and dry the dirty cartridge properly without leaving the tub unfiltered. If cloudy water is the symptom, start with the cloudy water filter checklist. For replacement timing, use how often to change a hot tub filter.