Cleaning Your Filter
Rinse your filter cartridge every couple of weeks, although if you’ve used it a lot or have had a particularly large bather load, do this more often. Simply remove the filter — while the hot tub is off — and use a garden hose to rinse the filter well. Keep the stream of water at a 45-degree angle and spray between each of the filter's pleats. Let it dry completely before you reinstall it. Don't use a high pressure nozzle, a pressure washer, or your dishwasher to rinse the filter. High pressure water streams can damage the filter’s fibers.
Soaking Your Filter
Every time you change the hot tub’s water or every three or four months, a more thorough cleaning is in order. Rinse the filter the same as you normally would and then soak it overnight in a cleaning solution meant for hot tub filters. Don't use regular detergents such as dish soap or dishwasher detergent as these can remain in the filter’s fibers and cause problems with foaming when the filter’s back in the hot tub. After the soak, rinse the filter again and let it dry completely before reinstalling it.
Replacing Your Filter
Replace any filters that are a year old or more or any filter that appears to be damaged or refuses to come clean. A hot tub filter not only keeps the water cleaner, it prevents particulates and gunk from reaching the hot tub’s water pump. Older filters don’t do as good a job at this and can lead to a clog or broken water pump, which is much more expensive to fix. Whenever you remove your filter to clean it, inspect it for damage. If the plastic frame is cracked, the filter is separating from the frame or if you can’t get it to come clean, throw the filter away.
Keeping two filters and rotating their use is a good idea. It allows you to put in a clean, dry filter when you take the first one out for cleaning, and it means you won’t have to wait for the filter to dry before you can use your hot tub. Allowing a filter to dry completely after it’s been cleaned helps to get rid of microorganisms, so it’s an important step that can sometimes get skipped. Rotating your filters will also increase their useful lifespan.