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Filters play an integral role in hot tub water quality

How to maintain a hot tub filter

A high-pressure, fresh-water stream should be used to rinse the filter.
A high-pressure, fresh-water stream should be used to rinse the filter.

Service professionals should advise hot tub owners to get into the habit of removing their filter on a weekly basis to give it a fresh water rinse. In warm climates, this can be accomplished with a garden hose. If it is cold outside, the filter can be rinsed in a utility sink or bathtub inside the home.

The hot tub owner can also use aftermarket hose attachments (e.g. comb-like spray nozzles) that are designed to help rinse the filter pleats. This simple step will go a long way toward keeping the filter cleaner, as well as prolong its life.

There are also several products on the market to give a filter a deeper, chemical rinse. These products work adequately to remove loose particulates. Some require an overnight enzyme soak, while others involve placing the filter in the water, in the centre of the hot tub, when performing a plumbing line purge. The scouring agents used to clean out the lines beneath the hot tub are also strong enough to clean the filter pleats. When using any one of these chemical cleaning methods, ensure the customer’s filter is thoroughly rinsed before reinstalling it in the hot tub’s filter compartment.

The cleaning methods outlined above work for most paper-media filters. There are ceramic filters available as well. If a hot tub is equipped with one of these types of filters, which are typically more expensive, the service technician should check the manufacturer’s recommendations before cleaning. In many cases, the filter’s ceramic plates become coated with slime, which can be rinsed or wiped off and replaced.

Finally, there are two home remedy methods that some hot tub owners have used over the years to clean their filters—dishwashers and bleach. If the homeowner asks about these types of cleaning procedures, this author would only recommend the first option should the homeowner desire. However, before running the filter through a dishwasher cycle, advise the homeowner to make sure the filter is dishwasher safe as per the manufacturer.

As for bleach, this is a popular mistake many make when cleaning filters. Sure, bleach does a great job of making the filter look white again, but what happens is the paper media becomes corroded by the harsh chemical and, as a result, the filter life is reduced. The idea behind cleaning a hot tub filter is to ensure it is working properly, not look whiter. The filter is going to get dirty, as that is its job.

When is a new filter required?

When a filter becomes clogged beyond the point of rinsing, or if the media has eroded, a service professional should advise the hot tub owner that it is time to purchase a replacement. When replacing a filter—whether performed by a service professional or the homeowner—it is important to reference the hot tub’s operating manual to ensure the proper media is selected and is sized correctly. A good tip is to measure the existing filter first.

There are many different options for filters, including the size of particulates that they remove (microscopic differences between tiny and super small), which is why it is important to compare the dimensions of filters with specified data in the operator’s manual.

Hot tub filters need care and replacement just like the filters used on a household furnace and vehicle.

AuthorColin Taylor, B.Sc., MIScT, is a chemist for SilkBalance, a hot tub water care company based in Vancouver, B.C. He has been involved in addressing several hot tub water maintenance problems and focuses on resolving and simplifying them. Taylor also answers many e-mail questions from hot tub users around the world. He can be reached via e-mail at

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