How to Get Rid of Hot Tub Algae

By Calvin | Last Updated: May 29, 2021 | Maintenance / Water Chemistry

Having algae bloom in the hot tub isn’t something anyone wants. Algae in your hot tub make it unsafe and very unhealthy. Taking a dip in algae-infested hot tub water will not just give you skin infections. It will also make you sick.

So what causes algae growth in your hot tub? And more importantly, how can you get rid of hot tub algae? The answer to these questions and everything you need to know about controlling algae growth in your hot tub will be revealed below.

When you are done reading this post, you will not only know how to get rid of hot tub algae but also how to prevent them.

So let’s get on with it.

No one wants to see green water in their hot tub. But, sometimes it happens. If it happened to you, don't worry. We will teach you how to get rid of hot tub algae and how to prevent it from happening again.

How to Get Rid of Hot Tub Algae

Getting rid of hot tub algae is a fairly lengthy process. It involves adding sanitizers and other chemicals to the water. Depending on the level of algae growth, you may also need to drain and clean the shell of the hot tub.

All of these steps need to be carried out correctly, so this isn’t a task to take on in a rush. The following steps will guide you on how to get rid of hot tub algae.

Know the Type of Algae You Are Dealing With

The first thing to do before trying to get rid of the algae in your hot tub is to know what type of algae you are dealing with. Knowing which type you have in your spa will help you figure out what caused it and, more importantly, how to prevent it.

Three common types of algae growth affect hot tubs. The green algae, black algae, and yellow algae.

The green algae are the most common, and this is what you will most likely have in your hot tub. Green algae are usually caused by low levels of sanitizers like bromine and chlorine in the water. If you notice that the water in the tub is turning green, you are most likely dealing with green algae.

Yellow algae are also caused by low levels of sanitizers in the water. This can also be caused by poor water chemistry or a very low ph level. The yellow algae aren’t exactly bright yellow. It has a mixture of green and yellow colors in the water.

Black algae can be caused by different reasons ranging from low ph levels and sanitizers to hot tub scum. This is the most difficult type of algae to get rid of. It appears as small black patches on the walls and on the surface of the water.

Though there are different types of algae, they can all be eliminated through the same method.

Adjust the pH Level of Your Hot Tub

The next thing to do is to adjust the ph level of the hot tub. Algae growth is facilitated by low water ph. So adjusting the water ph to the right balance might just work for you. Start by testing the ph level of the water. This can be done by using hot tub testing kits or by taking a sample of the water to the lab to be examined.

Chances are the ph level is low. If this is the case, you can use a ph increaser to up the ph level of the water. You can also start by using a water clarifier, but you should know that this is usually a temporary solution. In most cases, a water clarifier will not get rid of the algae permanently.

Related Read>>> How To Remove Hot Tub Scum?

Shock the Spa

Nothing gets rid of germs, bacteria, and algae in your hot tub like a good old shock. This step involves adding a high amount of sanitizer to the water. You can use chlorine, bromine, or non-chlorine shock to shock the water.

You should, however, exercise caution while doing this. Hot tub shocks usually have specific instructions regarding their application, so follow all the instructions or seek the help of a professional.

Drain the Hot Tub

Yes, you need to drain the hot tub, especially if you suspect there is a severe case of algae blooms in your hot tub. Algae are microscopic plants that multiply in numbers. You usually would not see or even notice that you have algae in your hot tub till there are millions in it.

So if you notice the algae in the tub, then it’s best to just drain the tub because, by that time, you already have millions of unwanted guests sharing your hot tub. It is also advised to drain the tub even after shocking it. This may seem like a waste of time, effort, and sanitizers, but it is the most effective way to permanently rid your hot tub of any algae growth.

Clean the Shell of the Hot Tub

After draining the tub, you need to clean the shell of the tub. The shell includes the walls and frame of the hot tub. You should use a hot tub cleaner or a mixture of detergent and baking soda to clean the hot tub’s shell. This step will eliminate any traces of algae that may be stuck to the hot tub walls.

You should pay attention to the jets, filters, and base of the hot tub while cleaning the shell. It would be better to take out the filters for a good clean, or you can replace them. After cleaning the shell of the hot tub, leave it to dry.

Refill the Hot Tub

You should refill the hot tub when the tub has fully dried. While refilling the tub, ensure to use a hose filter to prevent the build-up of solids and metals like iron and copper in the water. You should also add sanitizers to the water after refilling it. This will prevent the formation of algae over again.

If it’s a severe case of algae bloom, you might need to drain, refill and shock the hot tub at least twice to be sure you don’t have any algae in the water after.

Related Read>>> How To Remove Hot Tub Foamy Water?

Clean the Hot Tub Cover

covering your hot tub with a dirty cover means you are directly causing the problem you just got rid of. There are different spa cleaning products out there that you can use to clean the cover of the hot tub.

After doing all of the above, you should wait for at least 24 hours before using the hot tub. This will give you enough time to monitor the state of your hot tub. It will also allow the sanitizers you added to the water after refilling it to work effectively.

Now you know how remove hot tub algae, but what causes the algae in the first place? Keep reading to find out.

What Causes Hot Tub Algae?

Hot tub algae are caused by different reasons, all of which can be grouped under poor hot tub maintenance. Let’s take a look at some of the reasons why you might be having algae in your hot tub water.

Uncovered Hot Tub

This might not seem like a big deal at first, but it is, especially if your hot tub is installed outdoors. Algae are microscopic plants, and just like every other plant, they need sunlight to thrive. Algae can survive by making their own food through photosynthesis (sunlight).

So if your hot tub is left uncovered and under the rays of direct sunlight, then you are providing food for the algae to bloom. A good idea is to always keep your hot tub covered when not in use.

Used Hot Tubs

Not everyone has the funds for a new hot tub. If you bought a used hot tub, it might have been affected by a nasty case of algae bloom before you purchased it. The good idea is to clean and disinfect used hot tubs thoroughly before using them. Don’t just add water to the tub and soak in it.

Low Level of Sanitizers

Another possible reason you are dealing with algae in your spa is that the level of sanitizers in the water is too low to combat algae growth. The chlorine, bromine, or whatever sanitizer you use to clean your hot tub has to be added in the right amount. Anything less can cause algae and bacteria to grow in the tub.

Another factor similar to this is a low ph level. If the ph level is low, then algae can grow in the water. A good idea is to always add sufficient sanitizers to the water and to keep the ph level at the right amount. As an expert tip, keep the ph level above 7.4 and the alkalinity above 100 ppm (parts per million).

Damaged Filters

The filtration system in your hot tub is meant to trap dirt and debris in the water. The filters trap the unwanted particles in your water and stop them from being circulated with the water in the hot tub. If the filters are damaged, worn out, or even dirty, then there is nothing stopping dirt and debris from being circulated in the water.

This will allow not just algae growth but also hot tub scum and other bacteria in the water. Other causes of algae in your hot tub include body care products, bodily residue, too many users in one hot tub, leftovers, and the likes. So how can you prevent hot tub algae? Let’s find out.

Related Read:  How Often Should You Clean Your Hot Tub Filters?

How to Prevent Hot Tub Algae

Preventing hot tub algae takes dedication and a steady hot tub cleaning routine. The following tips will help you prevent algae growth in your hot tub.

Maintain a Good Water Chemistry and pH Level

By keeping the pH level and water chemistry balanced, you are directly eliminating any possibility of having algae growth in your water. Like all living organisms, algae also need specific conditions in your hot tub to survive. If the ph level is low and the water chemistry is off, that presents a perfect living condition for algae.

So always ensure the water chemistry and the ph level are at the right amount. A good way to do this is to regularly test the pH level and water chemistry of the tub. If the ph level is low, you can use a ph increaser to increase it.

Related Read>>> How to Lower Alkalinity in a Hot Tub?

Drain the Spa Regularly

You should always take time to drain and clean the shell of the spa regularly. You can do this once or twice a month to prevent algae growth.

Always Use Sanitizers

Sanitizers and chemicals should be added to the water on a regular basis. The sanitizers should also be added correctly to prevent a case of a low level of hot tub sanitizers. You should add the chlorine at a range of 3 to 5 ppm and the bromine at a range of 2 to 4 ppm.

Always Keep the Hot Tub Covered

Always cover the hot tub with its cover or lid when the tub is not in use. This prevents algae from getting the sunlight needed for their survival.

Clean and Replace the Filters Regularly

The filters in the hot tub should be cleaned or replaced on a regular basis. If the filters are clean and working well, the dirt that can cause algae growth in the water will be trapped and wouldn’t be circulated with the water.

Other methods of preventing algae growth in the hot tub include limiting the number of guests that use your hot tub and shocking the hot tub.

So there you have it. Now you know how to prevent and get rid of hot tub algae. Be sure to leave a comment below if you found this post useful. Have a nice day.

Hi, I'm Calvin Hall, the owner of Hot Tub Wiki. I worked at a local Spa Service for a few years before creating this website. I have owned several hot tubs and fixed a thousand of them. So, I know a thing or two about hot tubs.