Overtime, filters will become dirty and clogged, it is important to keep your filters clean to maintain good water quality and to protect the internals of your spa. Remove your filter and place in a bucket of filter cleaner, leave it to soak for at least 24 hours, this will allow the cleaner to break down any oils, grease and other contaminants that are sitting in your filter. Once this is done we recommend hosing your cartridge to remove any leftover cleaner and to rinse the dirt away. If you live in a hard water area your filter may need to use a pressure cleaner to remove any calcium build-up. Depending on how often you use your tub we suggest doing this every 3 months.