NOTHING IS MORE IMPORTANT FOR HOT TUB WATER QUALITY THAN YOUR FILTERING SYSTEM.
No matter what chemical combination you use, it will not help if your tub has a dirty, clogged, or worn-out filter. A dirty filter will fail in its job of trapping contaminants, and put strain on your spa's pump. Clean your filter at every water change, and replace it with a brand new one annually.
Rotate Your Spa Filters
Use the filter rotation method. While your dirty filter is being cleaned, swap it with a clean, dry spare. With this system you'll never have to wait to use your spa. Your filters will last longer, and work more effectively. Allowing filters to dry completely after cleaning will help destroy any resident microorganisms.
Manual Cleaning
Hot tub filter cartridges should be rinsed every two weeks and more often if the hot tub is used heavily. Use a garden hose with a nozzle at a 45 degree angle making sure to dislodge all foreign matter, especially between the pleats. Always install a fully cleaned and dried filter with every water change. A water change is commonly done every 3-4 months. This schedule is suited to regular use of the tub by the same people. When a variety of different people are using the tub, it is advisable to check water chemistry  more often. 
FilterTips
Spray, soak, spray, dry.
When you soak your filter (overnight is adequate) adding a small amount of cartridge cleaner is suggested. Avoid laundry detergents and household cleaners; you may have a major foaming problem with your hot tub if you use them.
Use a product designed for cleaning pleated filter cartridges. Household bleach will work as a cartridge cleaner, but it will shorten the filter’s life span.
When cleaning, always rotate out your filters with a clean, dry spare.
We recommend that filters be completely replaced annually.
Never use a power-washer or dishwasher to clean filter cartridges. The high water pressure will damage the media. Be gentle if you use a brush.
Always follow your equipment manufacturer's instructions for removing and reinstalling filter cartridges.
Reminders
Mark filter and water changing day on your calendar so you can keep track easily.
Ask your local hot tub store to keep your specific filter on hand. There are hundreds of different filters available, and most stores will only stock the most common unless asked. It’s comforting to know you can get yours quickly if need be.
Water chemistry is much easier to keep balanced if your filter is clean.
Your circulation pump doesn`t have to work as hard if the filter is clean.
If you have extra people in your tub at random times give your filter a spray afterwards, or exchange it with your spare as soon as possible. Adding shock at this time is helpful as well, regardless of what you use for sanitation.
Coast Spas offers an exclusive option called a refresh button. A refresh button allows you to filter your water at any point in the pre-set filtration cycle for 10 minutes. Press to refresh 10 minutes before using, and your water will be clean, clear and hot allowing you the most revitalizing soak experience possible.