Regular maintenance of a hot tub filter helps to prolong the life of the hot tub and maximize the efficiency of the tub, not to mention make the experience more hygienic by keeping the water clean. It's easy to clean a hot tub filter on your own with muriatic acid. You do not need any expensive equipment or special expertise, but as with working with any chemicals, you should be sure safety is a priority. Muriatic acid is dangerous and highly toxic. Many hot tub and spa owners opt to use milder cleaning solutions such as bleach/water or commercial spa cleaners instead.
Determine how often the filter should be cleaned by noting the size of the filter, how often the spa is used and how much debris gets into the water. As a rule of thumb, hot tub filters should be cleaned approximately once a month.
Shut off the power to the hot tub.
Locate the filter housing. Typically it is along the main water path and is usually visible inside the hot tub. If you can't locate the filter, refer to your owner's manual or to the manufacturer's website for further assistance.
Use the screwdriver to disassemble the filter housing and remove the cartridge.
Check the filter for damage including cracks, brittleness or extreme discoloration. If any problems are found, dispose of the filter and purchase a replacement. Hot tub filters should be replaced every year even if not damaged.
Use a garden hose with a nozzle attachment to spray off the filter until there is no trace of dirt or debris. Be sure to wash all the pleats, getting in between each pleat.
Put on safety goggles and gloves prior to handling muriatic acid. Soak the filter in a solution of 1 part muriatic acid to 20 parts water until all bubbling stops.
Rinse the filter well, then reassemble the filter housing and plug the hot tub back in.