A Helpful Guide To Hot Tub Green And Smelly Water (Algie, Copper, Pollen, Contaminates)

There will probably be a time when you find the water in your inflatable hot tub or hot tub has turned green. There is a possibility it may also have a smell emanating from the water.

You may be wondering why the water has turned green and smelly. This may be the first time this has happened which has brought you to this post. You may also be running through scenarios in your head of how to resolve, how much cleaning you will have to do. Do you have to sanitise and so on.

In this article, I will detail the potential reasons why your water has turned a green colour and I will detail the solutions. These solutions will be in the form of an action plan to complete to resolve the potential problem.

By the end of this article, you will have some action points to take to clean your hot tub and get rid of that green water.

What could be the cause of the green water in my hot tub

We can begin the investigation by looking at the 3 most common reasons and causes for green water in a hot tub.

  • Oxidation of Copper and other Metals
  • Insufficient Sanitiser
  • Pollen in the water

Oxidation of Copper and other metals in your hot tub

Although you may not think of metals if you have an inflatable hot tub, one of the common reasons for green water in a hot tub is the oxidation of metals, quite often Copper, in your hot tub water.

The process of oxidation of the Copper produces copper carbonate that will interact with the water and leave it with a green tinge.

Copper can be introduced to the water by an interaction between it at 1 or more metal components, such as the heater or air jets. Quite often Copper is utilised in the heater element due to its heat conduction properties.

There is also the possibility of some supplements added to the hot tub may contain high levels of Copper.

Insufficient sanitiser

We add sanitiser to our hot tub water to kill bacteria and any other unwanted contaminants. One such contaminate is algae.

Alfie in a hot tub is rare because most hot tubs are covered for a majority of the time. Alfie like most other plants need sunlight to grow and keeping the top covered prevents sunlight from entering.

However, there is still a chance that algae could grow. If it did a green tinge would be attributed to the cell growth or bloom as it’s referred to.

Common causes of Algae growth in a hot tub

There are a few common causes why algae may be growing in your hot tub

  • Leaving the hot tub uncovered
  • Having insufficient amounts of sanitiser
  • Bad filtration
  • An environmental issue or introduction of algae to the water via bathing suits or other

Pollen in the water

One of the lesser thought of reasons for green water in a hot tub is pollen.

Pollen is a fine powder which is the male part of a plant for its reproduction.

Pollen grains are extremely small and are easily carried by the wind. As they are small it will take a considerable amount to accumulate to see as a pollutant to the hot tub water.

However, pollen can accumulate in your hot tub and your filter may your filter system may struggle to remove it because it is so small. Once enough has accumulated you could get a yellow and green colour to your water.

How to remedy green water in your hot tub

The good news is, with the right treatment you can remove the green from the water and return to a clean and enjoyable hot tub.

Below are some solutions to this green water in your hot tub.

Option 1 – Treat the existing water

The first option is to treat the existing water in your hot tub. To do this you will need to examine your hot tub and water.

Examine the hot tub

First, feel the inner surface of the hot tub. Doing so will give you some helpful insights into the possible cause for the green water.

If the water is a cloudier green colour and the surfaces are a little slimy to the touch, this would generally indicate an algae problem.

If the water is green but still clear then this may indicate a high concentration of oxidised metals.

If pollen is your issue then it is likely it will settle on the bottom of your hot tub. This would create an ominous looking cloud that is stirred up at the slightest agitation.

Remedies to treat water

Here are some remedies you can try to clean up the water for each of the issues mentioned.

Removing oxidised metals

For any excess Copper issue, you will need to add a sequestering or chelating agent. This should cause the metal ions to group together in complexes.

Once grouped in complexes they are easier to filter out of the water.

Note: It is important to clean or replace your filter after using a sequestering agent.

Removing algae


When we say shocking your hot tub, this is not a jump out and say boo – more of a way to say super sanitise.

When we super sanitise we are saying we need to add a bunch of Chlorine, Bromine or whichever sanitiser you use, to kill the algae.

This is not the way I would recommend because adding the sanitiser can drastically affect the chemical pH levels in your hot tub. This would force you to drain and refill your hot tub anyway.

In a pinch, you could also try another way to get rid of the algae.

  1. Circulate the water continuously until the algae is gone.
  2. Make sure the hot tub filters are clean.
  3. Wipe down the interior shell so as to break down the algae clinging to it.
  4. Check that your pH level is between 7.4 and 7.6.
  5. Raise your chlorine level or bromine level.

You should start to see the algae disappear. If in 24 hours you don’t see any change, increase your sanitiser levels or drain and refill the hot tub.

Hot tub algaecide

Algaecide is usually designed to prevent algae, however sometimes using enough algaecide can effectively kill the algae.

Combine using this will circulating the water and wiping down the sides to loosen the algae.

Prevention algae for the future

Once removed, to prevent this problem from happening again, simply take care of your hot tub water – Keep the pH between 7.4 and 7.6 – Keep your alkalinity between 100 and 150 ppm (parts per million) – Keep your sanitiser level in the right range depending on the sanitiser you use.

Note: Please check the user instructions for your hot tub and any chemicals you use to ensure you use the correct amount

Removing pollen

A pollen accumulation can be remedied with the addition of a flocculant. A flocculant is a substance that promotes the clumping of particles and is used in treating wastewater.

Using a flocculant will clump together the particle of pollen and make them easier to filter out.

Note: As with most of these solutions, once clean make sure you clean or change the filter.

Option 2 – Drain and refill the water

The best option in most cases is to start with fresh water. To do this will need to drain, clean and refill your hot tub.

Drain your hot tub

Depending on if its an inflatable hot tub or hard shell hot tub, each has their own instructions and methods to drain.

For this step, check your hot tub instructions for the correct method to drain the water.

Clean the filter and spa

Once the hot tub is empty of water you will need to clean the hot tub surfaces.

Spray the surfaces of the hot tub with a spa cleaner, we recommend using the following items to clean your hot tub:

You may also try spraying a mixture of four parts water to one part white vinegar.

Remove the filter and rinse it with your garden hose, Then spray the filter with a filter cleaning chemical and leave for around 30 minutes. Then hose down once more. For deeper cleaning, I would recommend an overnight soak in a chemical soak with the filter submerged. Then rinse thoroughly once out.

Finally, reattach filter and refill the hot tub with fresh water.

In summary

Although green water can be unsightly and in some cases smelly; it doesn’t have to be a long term problem.

Using the remedies in this article you can clean and remove the contaminants and/or water from your hot tub and return to a crystal clean water hot tub to enjoy.

Please always follow instructions for your hot tub when using any chemicals in the cleaning of your hot tub or water contaminates.

Hot Tub Water Green And Smelly

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