Guide To Clearing Green Hot Tub Water

There are many signs that something is off with your hot tub water. For example, if you’ve noticed that the water has a green tinge, it needs maintenance. The first thing you need to do is determine the cause of the green coloring in the water, and, from there, you can find a solution.

Possible causes of green hot tub water include algae, insufficient sanitizers in the water, foreign products, and broken filtration. Each of these can be fixed, but first, you have to determine what the cause is in your hot tub specifically.

No matter what the cause of the green water is, you want to know what it is and what you to do about it so you can go back to enjoying your hot tub. So now, let’s take a closer look at how to determine what’s caused your green hot tub water and how you can fix it. 

What Causes Green Hot Tub Water?

Hotel Hot Tub

As there are a few different things that can cause your hot tub to take on a green or greenish hue, you need to look at each cause to identify the problem with your hot tub.


Algae is the most likely issue if you see a green color in your hot tub water. Algae is a green aquatic plant that can grow in water. Although chlorine usually takes care of the problem, if the water’s chemical balance is thrown off, it gives algae a chance to grow.

This is especially true if your hot tub is positioned in the sun. The sun can kill off chlorine quickly, which allows algae to thrive in a shorter time period.

Not Enough Sanitization

One simple reason the water looks green is that there might not have been enough sanitization. It’s not just algae that can grow; other bacteria can get into the water and cause cosmetic issues such as cloudiness and off coloring. 

Broken Filtration

A hot tub’s filtration system works to keep the water clean, filtering out any dirt and debris. However, if something goes wrong with the filtration system, then what can happen is that the water can become unclean. 

Foreign Substances

Foreign substances getting into the water could also cause it to become green. This could be anything from tree leaves and twigs from a storm to someone shedding shampoo and body wash into the water because they didn’t rinse off properly after a shower.

Is Green Hot Tub Water Safe?

Green hot tub water isn’t dangerous to humans for the most part—it’s just unsanitary. It isn’t toxic if it’s algae, the most common cause.

Even though algae isn’t dangerous, it’s still not the most comfortable or sanitary to swim in, so you should still work to fix it before getting back in the hot tub.

If it’s due to there not being a good chemical balance, it could cause people’s skin to become irritated and may even attack their nasal passages. This is especially bad for children and those with trouble breathing (like asthma).

How to Fix Green Hot Tub Water 

How you fix green hot tub water will depend on the cause, so let’s take a look at the solutions to each. But if in doubt, deep cleaning the hot tub should do the trick.

Get Rid of the Algae

If there are algae in a hot tub, it generally means that the chlorine balance is off. In this case, it’s a good idea to use a chlorine-free shock (on Amazon) to shock the hot tub and eliminate bacteria and algae. Once you’ve done that, you can work on bringing the chlorine levels back up.

Test the water to see the chlorine levels and add more chlorine to the water. Liquid chlorine is fine, but chlorine tablets (on Amazon) are better as they contain a stabilizer and come premeasured.

Sanitize Everything

If you haven’t kept up with the hot tub cleaning enough, that could be why you’re having issues. Generally, you will have to drain the hot tub and clean it thoroughly.

Once you’ve drained the water, take a rag and soak it in equal parts water and vinegar (on Amazon). You can then wipe around the hot tub’s shell and along the edge of the jets to ensure they aren’t blocked with anything.

You should also remove the filters and soak them in a water and vinegar solution or a specific filter cleaner (on Amazon) for at least an hour, preferably overnight.

Before you do this, rinse them down, and rinse them down again before you put them back. Never use a pressure washer on your filters, as this could damage them.

Check the Filters

You should take the filters out every week, give them a quick rinse, and check they’re still working. Filters have a lifespan of around two years if taken care of, so if it’s been longer than this or you haven’t been keeping up with them, you may need to replace them with new filters (on Amazon).

Remove Foreign Products

If there’s been a foreign product in the pool, you’ll need to do a deep clean the same way you would if there wasn’t enough sanitization. 

How to Prevent Green Water

Hotel staff african worker cleaning the hot tub

In the future, there are a few ways you can prevent problematic green water in your hot tub.

Keep Up with Maintenance

The best thing you can do is keep up with hot tub maintenance. Firstly, you should keep your hot tub covered when not in use. Use a well-fitting cover and rinse it down once a week to ensure nothing is getting in the water. You should also scoop out any debris and dirt that gets in there.

Rinse your filters once a week and at least every month or two, empty the hot tub and clean it. How often you do this depends on how heavily the hot tub is used. If you use it every day, you may need to do this every month, whereas those who don’t use it as much can get away with doing it every two or three.

You should also test the chemical balance and pH/alkalinity of the water at least weekly, adjusting it where needed. Keeping a supply of chlorine on hand for those moments is critical.

Use the Correct Methods

As well as keeping up with hot tub maintenance, you should use the correct methods. Do not, for example, use a bleach cleaner in the tub when a water and vinegar solution is just fine. Ensure you rinse any components after cleaning, like the filters, before putting them back in there.

Be Aware of What Goes in the Tub

A crucial part of looking after your hot tub is knowing which substances go in it. For example, you should never use things like bath bombs or other aromatherapy products in your tub unless they’re specifically designed for it. You should also never use body wash, shampoo, or conditioner.

It goes further than that, though. These substances can get into the hot tub just by being shed by humans! So make sure you rinse down thoroughly after being in a shower and getting into the tub.

You can also keep dedicated swimwear for the tub and prevent laundry detergent from muddying the water by rinsing that swimwear in cold water instead of putting it in the machine.

To Conclude

Overall, green water shouldn’t be dangerous to humans as long as it’s one of the most common causes—but it’s also not sanitary and often uncomfortable. An unsanitized hot tub, for example, can cause irritation, red skin, and blocked nasal packages.

The best thing to do is act fast if you see your hot tub turning green and prevent it from happening again by keeping up with the cleaning.

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