Follow the instruction of your pool filter to remove the filter cartridge.
Use a spray nozzle on your garden hose and spray at an angle to get
between the pleats. Do not use a pressure washer; it will damage the filter cartridge.
If the pool and spa filter is hard to be cleaned, soak it in filter
cleaner overnight. Make sure the cartridges are completely submerged in the water and cleaner mixture.
Check the filter tank O-ring on the filter tank. If it’s in good shape,
lightly apply some lubricant to keep it that way. If it’s dry-rotted, deformed, stretched, or appears
worn out, you need to replace it.
Rinse the pool & spa filter replacement cartridges thoroughly.
Put the filter cartridge back and secure them in place.