The filter is one of the most important pieces of equipment in your hot tub. Whenever your hot tub is running, the water is constantly being circulated through the filter, which is working hard removing leaves, bacteria, bugs, dead skin and other debris, to keep your water clean and safe. This guide will help you get to know your hot tub filter a little better.

Cartridge Filters

Cartridge filters are made of a fine, pleated mesh material that strains away debris. The hot tub water flows into a tank which contains one or more cylindrical cartridges made of this mesh material, which acts as a barrier to sift impurities out of the water.  Cartridge filters are the most popular type of filter used in spas and one of the easiest to maintain.

Maintenance Tips:

• In general, it’s a good idea to clean your cartridge filter at least once a month. To do this, simply remove the filter and use a garden hose to wash off dirt and debris.  You’ll also want to rinse off the filter whenever you change the water in your hot tub, even if you already cleaned it recently. If the filter is extremely dirty, you can also use a natural cleaning product, but it’s important to avoid using household detergents or bleach.
• It can be a good idea to buy two filters, so while you’re cleaning one, the other can be continuing to filter your hot tub water.
• Cartridge filters usually need to be replaced every 1-2 years, although the exact frequency depends on a number of factors, including how often you use your spa and the size of your filter.

Diatomaceous Earth Filters

Diatomaceous Earth filters consist of several fine mesh grids, which are coated with diatomaceous earth (DE). DE is a fine, white powder made from crushed petrified bones. The DE allows the clean water to pass through the filter, while trapping dirt and debris. Some hot tub owners prefer DE filters because DE is organic and does not pollute the environment.

Maintenance Tips

• DE filters need to be backwashed in order to stay clean. This is done by turning a valve that causes water to flow backwards through the filter, flushing out any debris. You can tell it’s time to backwash your filter when the pressure gauge reads 8-10 lbs above a clean reading.  Backwashing may need to be done every few days if you use your hot tub often.
• It’s usually a good idea to change the DE in your filter once every 30 days. Keep in mind that some municipalities have regulations regarding the disposal of DE.

Sand Filters

Sand filters contain a bed of sand, and the sharp edges of the sand grains are used to strain away dirt and impurities as the water passes through. Sand is not able to catch some of the most microscopic particles found in the water, and therefore it is the least effective of the three filter types.

Maintenance Tips

• Like DE filters, sand filters need to be backwashed regularly, whenever the pressure gauge rises 8-10 lbs above the clean.
• It’s a good idea to have the sand changed every 3-5 years. Keep in mind that filters use a special type of sand.
• Your sand filter actually works more effectively when it’s a little dirty, so it’s important not to backwash it or replace the sand too often.

Have a question about your hot tub filter? Visit one of International Pool and Spa’s locations across Ontario, and our hot tub experts can help you out.