Proper Hot Tub Filter Cleaning & Maintenance

Proper Hot Tub Filter Cleaning & Maintenance

You won’t see Hot Tub Filter Cleaning and Maintenance on anyone’s bucket list, but it’s one of the most important “must-do’s” for hot tub owners.

This task isn’t nearly as bad as most people would have you believe, but it can be if you don’t clean and maintain your filter in a regular basis.

You can’t have a healthy, safe and enjoyable hot tub experience without a filter, so it’s in your best interest to find out the most cost effective, least time consuming and easiest way to keep your filter clean.

Why Do Hot Tubs Need Filters?

• Filters protect your hot tub equipment from harsh or damaging particles in the water that can clog your system or damage your system’s components. Well maintained filters catch nasty particles before they do clog or damage your system.

• Filters also collect bacteria that goes unseen to the human eye. This creates a safer, cleaner and healthier environment for you, your friends and your family to soak in. Why worry about the dangers of pathogens in your hot tub water if you don’t have to.

• You’ll spend a lot less time picking debris, leaves and unwanted additions out of your hot tub if you maintain your filter on a regular basis.

• Not maintaining your hot tub filter may actually void the hot tub manufacturer’s warranty. That alone makes checking and cleaning your hot tub filter at least once or twice a month and replacing your filter every 6 months or once a year at the very least.

Quick Cleaning Vs. Deep Cleaning

Quick Filter Cleanings are easy, entail little or no chemicals and should be done regularly. The easiest method is to simply remove the filter, rinse it down well with a hose, let it dry and then put it back in the hot tub.

For a better, longer lasting clean, use an instant cartridge cleaner or a Water Wand Filter Cleaner.  You can spray most cartridge cleaners right on the filter, let it soak for a short period of time and then rinse it off with a hose.

The Water Wand Filter Cleaner, pictured on the right, is the worlds first hand-held cartridge filter cleaner. It is highly effective at cleaning all hot tub pleated filter cartridges in significantly less time and uses less water than traditional filter cleaning methods.

Deep Cleaning takes several hours, can be done overnight and should be done about every 6 months. Unlike Quick Cleaning, deep cleaning requires the use of a filter cleaning chemicals. The most common deep cleaning method is soaking your filter in a diluted solution of water and filter cleaning chemicals overnight in a bucket.

The bucket must be large enough so that your filter will be entirely submerged in the solution. For the best results, follow the manufacturer’s instructions and let your filter soak overnight. Remove the filter in the morning, rinse if off thoroughly with a garden hose and let it dry off completely before putting it back in your hot tub.

Basic Filter Maintenance Schedule:

• Quick Cleaning Once Every Two Weeks
• Deep Filter Cleaning Once Every 2-3 Months
• Filter Replacement Every 12 Months

If you have any questions or need further details about hot tub cleaning or maintenance, please call Roberts Hot Tubs toll-free at 1-800-735-5290 or email us at and one of our customer care representatives will be happy to help you.

Filter Cartridge Cleaning Process

Cleaning Instructions for Unicel Spa Filter Cartridges

Filter Cartridge Cleaning Process

1.    Remove the cartridge from the filter housing following the manufacturer’s instructions.

2.    Use a garden hose with a straight flow nozzle to wash down the filter element. Work from the bottom down, holding the nozzle at a 45-degree angle, and wash all the pleats with emphasis between pleats.

3.    Rinse until all dirt and debris is gone.

4.    For all spa cartridges and elements used in swimming pools where perspiration, suntan lotions, and other oils are present, soak the element for at least one hour (over night is most effective) in (1) a filter cleaner; or (2) one cup tri-sodium phosphate (tsp.) to five gallons of water.

5.    Rinse the cartridge again to remove oils and cleaning solution.

6.    If the filter has a coating of algae, calcium carbonate (residue from the calcium hypochlorite), iron or other minerals, soak the cartridge in a solution of one part muriatic acid to twenty parts water until all bubbling stops.

*WARNING: failure to remove all oils and cleaning solution before acid soaking will result in a permanent restriction of water flow and cause premature cartridge failure.

7.    Rinse the cartridge clean and reassemble housing.

Please Note: Unicel does not recommend the use of diatomaceous earth (DE) with cartridge filters. DE particles can become trapped in the body of the media and shorten cartridge life. If desired, a cellulose fiber (synthetic DE) can be used in moderation.

Baquacil as a Sanitizer

If you use baquacil as a sanitizer, the filter element must be cleaned with Baqua Clean before any cleaner is used.

Unlike chlorine, which oxidizes the bacteria in the water, the active ingredient in Baquacil, polyhexamethylene biqunaide or PHMB, destroys the bacterial cells. PHMB locates and binds to the bacterial surfaces, and then attacks the outer bacterial wall.

Once this wall has been compromised, the inner cell membrane, or cytoplasm membrane, is destroyed. This destruction allows the cell contents to disperse into their surroundings where they are further broken down into their elemental parts by Baqua Shock, a non-chlorine oxidizer.

In addition, Baquacil is a mild coagulant, which combines bacterial cells and other small particles in the environment into particles large enough to be trapped by the filter.

The resulting deposit is a gray sticky film on the media, which can only be removed with Baqua Clean. If trisodium phosphate (TSP) or any TSP type cleaner is used prior to stripping the film, the cleaner and the gray film will combine to form a gum-like substance.

Once this occurs, the substance cannot be removed from the media and the filter cartridge must be replaced.

WARNING: Follow all manufacturers’ instructions, warnings and precautions when using Baquacil, Baqua Shocks and/or Baqua Clean.

Proper Care, Storage & Shelf Life of Reagents

Reagents that are stored properly maintain have a much longer shelf life and maintain their maximum effectiveness than those that are improperly stored. This includes all reagents including liquids, powders, crystals, tablets and test-strips.

Reagents should not be stored in moist or damp areas and should be kept dry and moisture free at all times. Powders, crystals and acids are very stable and have an excellent shelf life if kept dry and aren’t exposed to sunlight.

The date of manufacture is not the controlling factor when it comes to reagent shelf life; the storage conditions are much more important. As with all perishables, reagents are sensitive to environmental influences and will last longer under controlled conditions.

Taylor Technologies Recommends the Following Care for Reagents

Storing reagents at a consistent temperature in the range of 36°–85°F (2°–29°C). Dramatic temperature fluctuations, such as being stored near a refrigerator or in the trunk of a hot car, causes reagents to rapidly deteriorate.

Avoid exposing reagents to prolonged direct sunlight. Most manufacturers use brown plastic bottles to help protect light sensitive reagents for this very reason, but prolonged overexposure to direct sunlight will quickly deteriorate any reagents effectiveness.

Keep reagents separate from other non-reagent water treatment chemicals.

Replacing reagent caps immediately after use and tighten them carefully to limit their exposure to air and humidity.

Don’t switch reagent bottle caps. Placing bottle caps on soiled surfaces, re-pouring reagents into possibly contaminated containers and touching test strip pads can easily contaminate reagents.

The experts at Taylor formulate their reagents to remain fully effective for a minimum of one year, with very few exceptions.

As a general precaution and rule of thumb, you should replace any reagents that are more than one year old or at the beginning of each new testing season.

Overlooked Hot Tub Care Tips

Here are some basic, but sometimes overlooked tips on prolonging the life and maximizing your enjoyment of your hot tub or spa.

Following these suggestions will help preserve your tub and equipment while making your water cleaner, safer and more clear.  As an added bonus, it will also save you time and money!

1. Oil and soap based products are public enemy #1 when it comes to keeping your hot tub or spa water crystal clear. Never use regular household cleaners for cleaning the inside or outside of your hot tub or spa.

These products contain soap and/or ammonia which are both harmful and unsettling for your tub’s water chemistry. They can also clog up and prematurely age your spa equipment and you could easily wind up with a giant sized bubble bath if you don’t get all of the soap out of your spa’s water system.

2. Swim trunks and bathing suits are also a common cause of foamy and unappealing hot tub and spa water.

Small amounts of laundry detergent remain in bathing suits after they have been washed and dried and the residual detergent ends up back in your hot tub’s water supply.

An easy fix for this issue is to simply run an extra rinse cycle when you wash your swimwear or you can always just re-rinse your swimwear by hand.

3. This is a good one that most hot tub and spa owners aren’t aware of. When your hot tub or spa is not in use, keep the Air Control Valves closed.   The image below shows air control valves from some of the most popular and well known spa manufacturers.

These valves or dials are usually located on top of or near the top of your spa and they allow air to mix with the water coming out of your jets.

This is great when your spa is in use, but not so great when it’s not.  To image on the right shows

Besides letting cold air into the spa water and increasing heating costs, it can also introduce air borne debris and algae spores that can cloud your water and increases your chemical usage.

4. Personal hygiene products should be used in the shower and not in your spa or hot tub. Even though this is common knowledge, it’s amazing how many soakers seem to forget this basic rule.

Hair spray, hair mousse, styling gels, deodorant, anti-perspiration, sun tan lotion, excess sweat, make-up and skin creams of any sort will cloud your water and clog your filter, reducing its life and increasing your maintenance time.



5. Floating oil-absorbing sponges such as the Dirty Duck are fantastic at reducing the amount of clogging oils that are sent through your filter.

Remember to squeeze them out occasionally and to replace them when they start to deteriorate or when they no longer float.



6. Make sure your filter cartridge is fully seated in the filter compartment. This ensures 100% of the water passing through the filter, rather than bypassing it. Remember to clean the cartridge once a month for maximum longevity and to replace it every 1 to 2 years.

The fibers of the cartridge start to break down and deteriorate after a while and won’t do an adequate job of filtration after a while. It’s a not a bad idea to have two filter cartridges on hand for your spa and use them on an alternating basis.

This way, while one is being cleaned by soaking in a “Filter Cleaner” solution, the other one can be used in your spa to reduce the down time of your spa.


7. Make sure to test your spa water at least once per week and always after adding new water. Make sure that the pH and TOTAL ALKALINITY is within the proper ranges.

This is MOST important. Either adjust the pH and Alkalinity manually each week, or use “pH Balance”.

If you’re using a liquid test kit be sure to clean it after every use, keep the solutions out of the sun and to replace them ever year.

Also, always get your sample water from at least 12 inches below the surface. If you’re using test strips be sure to replace them if they are 6 months past the expiration date.

8. One quick and easy way to vacuum debris from the bottom of your spa is to simply use a garden hose and siphon it out.

9. If you have an in-ground spa you know you should never drain the water if it’s rained in the last few weeks, or if the ground is wet (if you didn’t know this, glad you’re here). If you do it’s very possible that the spa will float out of the ground.

But if you find yourself in that position and you need to change the water here’s a neat little trick. Drop a sump pump in the bottom of the spa and spread a large sheet of plastic over the top of the water.

As the sump pump removes the water, run water from a garden hose on top of the plastic. If the hose and pump are running at the same speed the water level won’t drop and the old and new water wont mix.