What causes hot tub foam and how to get rid of it

What causes hot tub foam and how to get rid of it
Updated on 11/04/2022 by Nathan Bull

There are many causes of hot tub foam, and because it’s often the result of more than one, it can sometimes seem hard to fix.


If you’re in a pinch and need an immediate but temporary fix, you can use a hot tub defoaming product to remove the foam quickly. A defoamer will only prolong the root issue, so you’re better off treating the underlying problem(s). Once you know what causes hot tub foam, it’s easier to figure out how to get rid of it long-term.

Jacuzzi Defoamer 500 ml - Hot Tub Store
Jacuzzi Defoamer 500 ml
Jacuzzi Defoamer eliminates and prevents foaming in your spa. Hot tub foam accumulates on the surface of the water, which makes for a thick and unhygienic nuisance. You can prevent the buildup of foam by using the best spa defoamer. Jacuzzi Defoamer is a chemical solution that prevents the water from developing the layer of foam. Size: 500 ml   Click here for Safety Data Sheet (SDS)


What causes hot tub foam?

Low or inconsistent sanitizer levels

Most foamy, cloudy, or discoloured water issues have to do in some way with low sanitizer (chlorine or bromine) levels. If your sanitizer levels aren’t maintained high enough, bacteria, algae and other organisms start to grow, and with it, hot tub foam is not far behind. When sanitizer levels are too low, it doesn’t take long for water issues to arise, and the longer they are, the more difficult it becomes to treat.

Jacuzzi Chlorinating Granules - Hot Tub Store
Jacuzzi Chlorinating Granules
from $22.95 $41.25
Tip: Download the AquaChek Smart app to make water balancing a breeze. Know "what" and "how much" based on your strip colours. Sanitize your hot tub with Jacuzzi Chlorinating Granules Jacuzzi Brand Chlorinating Granules is a stabilized chlorine for your spa that provides effective sanitation as a soluble, quick-dissolving oxidation treatment. Promoting water clarity, eliminating odours and organic waste such as body oils and cosmetic products. This powerful sanitizer is fast dissolving and can be used for both regular daily chlorination as well as super chlorination. Chlorine will not affect pH or total alkalinity nor will it promote scale build-up. The chlorine level in your spa should be maintained between 1-5 ppm. Ideal spa pH: 7.2-7.8 Ideal spa Alkalinity: 100 - 160 ppm  Size: 1.5 kg or 720g Click here for Safety Data Sheet (SDS)
Jacuzzi Bromine Tablets - Hot Tub Store
Jacuzzi Bromine Tablets
from $38.95 $79.99
Sanitize your spa with Jacuzzi Brominating Tabs Jacuzzi Bromine Tabs provide effective sanitation as a soluble oxidation treatment. Promoting water clarity, eliminating odours and organic waste such as body oils and cosmetic products.   Jacuzzi Brominating Tabs should be used with Spa Shock on a weekly basis to maintain effective levels of sanitizer in your spa. Bromine Tabs require water flow to dissolve and should be placed in a floating dispenser and should not make direct contact with the spa or bleaching can occur. Bromine is an alternative for Chlorine and can be used over a wider range of pH levels making it more forgiving in balancing water chemistry.    The bromine level in your spa should be maintained between 3-5 ppm. Ideal spa pH: 7.2-7.8 Ideal spa Alkalinity: 100 - 150 ppm  Weight: 1.5 kg Click here for Safety Data Sheet (SDS)


Keep your sanitizer levels between 3-5ppm for safe protection. If you experiment with anything lower, you’ll want to ensure you have and maintain a UV-C system like Jacuzzi ClearRay. You will also likely need to supplement your sanitizers with something like Spa Solution or a mineral sanitizer like Nature2 or Jacuzzi ProClear; if you choose to experiment with this route, make sure you keep your sanitizer at a minimum of 1ppm.

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ClearRay Replacement Bulb - Hot Tub Store
ClearRay Replacement Bulb
$155.95 $203.79
The ClearRAY system uses UV-C technology to neutralize waterborne pathogens, rendering them useless. ClearRAY will also help reduce the amount of sanitizer you use in your hot tub, providing you with clean, fresh clear water. For the cleanest, softest water possible. No more drying out, no more red-eye.  The ClearRay bulb needs to be replaced once a year. Detailed instructions on replacing your ClearRay bulb can be found here.   Replacement recommended every 12 months. 
Spa Solution - Hot Tub Store
Spa Solution
from $54.95
Spa Solution is a proprietary enzyme-based spa conditioning formula. Reduce the effects of harsh chemical additives in your spa. No more skin or eye irritation, rashes, or allergic reaction to spa use. Simply apply once every three months and enjoy your spa! This product is so safe, it requires no warning labels! So easy to use. Pour it in your spa and forget about it. Water so clean and clear you won't need to shower after using your spa. Never again suffer from burning eyes, dried skin, and irritating rashes. Reduce your dependency on harmful chemical additives. No more time-consuming water balancing and chemical adjusting. So economical- A purchase can last three months. 100% Non-toxic to all living creatures.
Nature2 Spa Stick - Hot Tub Store
Nature2 Spa Stick
from $49.95 $149.85
Description Nature2 Spa Stick works with your spa filter to give you clean, clear water with less hassle. Details Nature2 SPA is perfect for spa owners looking for an eco-friendly, low maintenance solution for keeping their spa clean and clear. Nature2 SPA uses a mineral bed technology that works with your Health Canada approved sanitizer to effectively control bacteria. Nature2 SPA works by automatically dissolving trace amounts of mineral elements into the water. Those elements act as a clarifier to help keep your water clean, clear, and scum-free. Just drop the Nature2 SPA stick into the spa's filter and forget about it for up to four months! Eco-friendly way to remove organics, irritants, and metals. Eliminates chemical odours. Low maintenance; lasts up to four months. Directions The Nature2 Stick sits inside your spa filter, resting in/on the filter pipe. It is very important this pipe is not obstructed. Spa models like the Jacuzzi J-300, J-400 and J-500 series have a grated pipe to prevent this. Assemble Nature2 Stick to needed length - when placed in filter it should sit near top Remove top of filter Place Nature2 Stick inside filter Put top of filter back on
ProClear Spa Sanitizer for Jacuzzi® Brand Hot Tubs - Hot Tub Store
ProClear Spa Sanitizer for Jacuzzi® Brand Hot Tubs
from $49.95
The ProClear Spa Sanitizer delivers a more efficiently sanitized, easily maintained, and odour-free hot tub. ProClear also significantly improves the look and feel of your water by providing a more consistent PH balance. Using trace elements of silver, ProClear kills bacteria more effectively than chlorine alone. It does this through an interaction with your regular dose of spa shock. When the special mixture of silver and minerals come in contact with MPS Spa Shock, a mild sanitizer is released into your spas water. This lowers the demand for chlorine and your spa water is not only brilliantly clear and soft but gives you an alternative to chlorine-intensive treatments. Use in conjunction with the CLEARRAY Water Purification System for clean, clear water. Reduces chlorine demand and requirement by up to 50% Naturally softens water Prevents pH bounce and helps stabilize your water's pH Requires weekly dose of sanitizer Requires Spa Frog Mineral Sanitizer in place of the ProClear Minerals. Compatible with Jacuzzi® J-500, J-400, J-LX & J-300 collection hot tubs. 


While low sanitizer is likely not the only reason for foamy water, it’s a must to treat when solving this problem. If you usually maintain your hot tub at 1-3ppm, bring it up to 3-5ppm until this problem is solved.


High total dissolved solids (TDS)

TDS measures the total amount of dissolved solids in your water - minerals, metals, salts, soap, lotion, body oils - pretty much anything that dissolves in your hot tub water. TDS is one of the primary reasons your hot tub needs to be drained every 2-4 months. When your hot tub has too many solids, you’ll get foam.


TDS should not measure more than 2000-3000ppm - you can test this using a TDS meter which you can find in hardware stores or on Amazon, or having your water tested by a local pool or hot tub store.


Soaps and detergents

Like a bath, when soap gets added to your hot tub, it creates foamy bubbles. Common sources of soaps and detergents are bathing suits, shampoos and cleaning agents. To help prevent this, rinse your bathing suit before entering the hot tub and if you have long hair, try keeping it above the water.


Oils and lotions

Hair conditioners, creams (hand and body), lotions, and oils (including body oils) contribute to the foam. Quickly rinsing off in the shower, especially after an intense workout, can help.



If your foam is oily and discoloured, your water feels slimy, or you have large white flakes, you’re probably dealing with biofilm, which you’ll want to address immediately. See our article on how to get rid of biofilm.


The best hot tub foam treatment

  1. Clean your filters. You may need to do this multiple times over a couple of days after letting your filtration system run for a few hours or overnight.
  2. Do a water test and balance your water, but don’t add your sanitizer (chlorine or bromine) just yet - just pay attention to it.
    Pro Tip: When water chemistry is out of balance, sanitizers won’t work effectively.
    • Sanitizers work less efficiently if pH is too high or low
    • Alkalinity stabilizes pH
    If your stabilizer level is above 60ppm, your sanitizer will become ineffective, and it’s time to drain and refill your hot tub.
  3. Shock your hot tub and run it for one full 20-minute cycle. Add your sanitizer. While you’re dealing with foam, you’ll want to keep your chlorine at or above 5ppm until it stops occurring when using the jets.
  4. Run your filtration system 24/7 until you are no longer experiencing foam. Consult your owner’s manual if your hot tub is not set to run filtration all day.


Optional: Add a Zorbie or clarifier to your hot tub to speed up the process.

Zorbie - Hot Tub Store
from $23.95 $72.00
The original Zorbie does a great job absorbing body oils, suntan lotions, make-up, dirt grime and lots of other stuff that gets into your hot tub water.  PLUS, due to its unique ion exchange capability, Zorbie also helps reduce spa & hot tub odours! Zorbie's tried & true flow-through action lets water pass right through while trapping odours & oils while absorbing about 20 times its own weight in unfilterable debris! Just throw it in the spa (best when used near the filter).  The more stuff it absorbs, the heavier it gets and sinks.  When it's really dirty & sinking, simply throw it away. Lasts 30 to 90 days. DO NOT SQUEEZE OR WRING OUT!
Jacuzzi Spa Clear 500mL - Hot Tub Store
Jacuzzi Spa Clear 500mL
Description Keep your hot tub water crystal clear and sparkling with Jacuzzi Brand Spa Clear. This clarifier will make your spa water sparkle. Details Spa Clear will not affect the water's pH level. It is non-toxic, pH neutral and can be used with all sanitizers. Size: 500mL Directions Add 1.5 tablespoons when refilling spa Add 1 tablespoon per week


If you can’t get rid of hot tub foam within three days using this method, you’ll likely need to drain and refill your hot tub.

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