Can You Use Pool Chemicals in a Hot Tub?

Hot tubs and swimming pools are usually sanitized with chemicals to keep the water clean. So can you use pool chemicals in your hot tub? Here is the answer to that.

You shouldn’t use pool chemicals in your hot tub because the pool chemicals will unbalance the water chemistry of the hot tub and cause several damages to the hot tub components.

So how do pool chemicals harm hot tubs? If you can’t use pool chemicals in a hot tub, can you use hot tub chemicals in a pool? There is more to know about pool and hot tub chemicals and this post digs right into the topic.

Let’s dive in.

Are Pool Chemicals The Same As Spa Chemicals?

Pool chemicals are not the same as spa chemicals. Though both chemicals might go by the same name and even the same brand, they are different in terms of concentration.

There are several reasons for this difference in concentration between the pool and hot tub chemicals. The main one is because of size. Swimming pools are usually larger than hot tubs. The average swimming pool is about ten times larger than a hot tub. The larger size of the pool means it will need a more concentrated chemical to keep it clean.

Another reason for the difference in concentration is the number of bathers. On average, a hot tub will fit 5 people, 7 at most. Swimming pools on the other hand can fit dozens of swimmers. The higher number of people using the pool means there will be more contaminants in the water.

Food residue, hair, oils, sweat, sunscreen, and the likes that get introduced into the pool will be way more than what is deposited into the hot tub. This means pools need aggressive chemicals to destroy the contaminants in the water.

The water in the hot tub is also hotter than the water in the pool. The hotter hot tub water temperature affects how the chemicals react in the water. This means hot tub chemicals are designed to be more stable than pool chemicals.

Hot tubs also have jets that disperse the chemicals easily in the water. Pools don’t have jets which means the chemicals need to be differently concentrated than hot tub chemicals.

Hot tubs also have more evaporation than swimming pools since hot tubs are usually heated. When water is being evaporated, you need less chemicals to clean the water.

So the chemicals might look the same, but they are very different.

Can You Use Pool Bromine Tablets In A Hot Tub?

Can You Use Pool Bromine Tablets In A Hot Tub?

You can use pool bromine tablets in a hot tub and you can use hot tub bromine tablets in a pool too. This is because bromine is not categorized by concentration.

Bromine sanitizer comes in tablet form. Unlike chlorine that comes in different forms, bromine only comes in tablets. So to add bromine to the water, you just need to add a specific amount of tablets to the water by using a floater or tablet feeder.

The required amount of bromine tablets will be put inside a floater or tablet feeder and placed on the water. The bromine tablets in the floater will gradually dissolve in the water over time and sanitize the water.

So with bromine, you can use the same tablets for both the pool and the hot tub. What changes is the amount of bromine tablets you will need. For pools, you will need to add 17 tablets for 10,000 gallons of water, and for hot tubs, you need 3 tablets for every 300 gallons of water.

Bromine sanitizer is also very good in high water temperatures. This makes bromine tablets very ideal for hot tubs. It also makes bromine tablets ideal if your pool is located in hot areas.

Since you can use pool bromine tablets in a hot tub, can you also use pool chlorine in a hot tub? Is pool chlorine the same as hot tub chlorine? Let’s take a closer look.

Related Read: Can You Use Bromine in a Chlorine Hot Tub?

Is Pool Chlorine The Same As Hot Tub Chlorine?

Pool chlorine is not the same as hot tub chlorine. Pool chlorine is usually more concentrated and potent than hot tub chlorine and it usually comes in liquid form which is the most potent of all the chlorine forms. Hot tub chlorine on the other hand usually comes in tablet or powder form.

You will only be advised to use liquid chlorine in your hot tub if you have a severe algae problem or when you want to shock the hot tub.

Pool chlorine is stronger than hot tub chlorine and this is due to several reasons.

For starters, pools are common for parties and social events which means there would be a lot of scum in the water. Hot tubs don’t have as many contaminants as pools. So hot tub chlorine is usually weaker than pool chlorine.

Pools are also larger than hot tubs. The larger size means more water to sanitize and stronger chlorine is needed.

Pool chlorine also has additional chemicals that help with balancing and dispersing the chemical in the pool. Pools have a lot of action that can affect the water pH level. People coming in and out of the pool frequently means pool water chemistry is often unbalanced.

So pool chlorine had additional chemicals that help the chlorine remain stable in the water despite the heavy action.

Hot tubs on the other hand don’t have as much action as bathers just sit inside the water for hours. So your hot tub chlorine is easily balanced and dispersed in the water without much effect on the pH level of the water.

So what happens if you use pool chlorine in your hot tub? Let’s find out below.

Related Read: How To Raise Chlorine Levels?

What Happens If You Use Pool Chlorine In Your Hot Tub?

If you use pool chlorine in your hot tub, the chlorine chemical will be too strong for the hot tub to handle. The liquid pool chlorine will disrupt the water chemistry of the water, lower the pH levels, put the total alkalinity off, and cause deterioration and corrosion of the hot tub components in the long run.

What Happens If You Use Pool Chlorine In Your Hot Tub?

When you add liquid pool chlorine to the hot tub, the first thing you will notice is that the chlorine level in the hot tub is very high. Liquid pool chlorine can raise the chlorine level in the hot tub over 10 ppm and hot tubs aren’t meant to have more than 5 ppm of chlorine in the water.

The high chlorine levels will lead to a lower pH level in the water. It will also offset the total alkalinity and water chemistry of the water. When the water chemistry and pH levels are off-balance, the hot tub components will get damaged.

The rubber seals around the hot tub components like the o-ring will harden and begin to break off. The shell of the hot tub will become stained and discolored. Three will be acidic water in the hot tub which will eventually eat away at the metal parts of the hot tub like the jets, circulation pump, and heater.

The hot tub water will also become very uncomfortable for users. So whatever you do, never use liquid chlorine or pool chlorine in your hot tub. Always read the instructions to know which is for a hot tub and which is for a pool.

Do Hot Tubs Need More Chemicals Than Pools?

Hot tubs do not need more chemicals than pools because hot tubs contain less water than pools. Hot tubs also have fewer contaminants than pools, so hot tubs don’t need as many chemicals as pools.

In terms of the types of chemicals used in hot tubs, hot tubs have quite a few chemicals. There is an alkaline increaser, alkaline decreaser, water clarifier, pH increaser, pH decreaser, hot tub cleaner, and the likes. So in terms of the types of chemicals added to a hot tub, hot tubs might require more types of chemicals than pools.

But when it comes to the volume or amount of chemicals added to the water, pools use way more chemicals than hot tubs. For instance, while a 600-gallon hot tub will require about 6 tablets of bromine, a medium-sized swimming pool that contains about 10,000 gallons of water will require 17 tablets of bromine every 5 days to sanitize the water. That’s way more bromine than the hot tub will use in say, 3 months.

Pools also need chemicals more frequently than hot tubs. With a hot tub, you might need to add chemicals to the water every month depending on how much you use the hot tub and the type of sanitizing system you are using. Salt water hot tubs for instance need hot tub salt once in 3 months.

Pools on the other hand require chemicals in days. You rarely can go a week without adding chemicals to your swimming pool. This is because swimming pools are usually uncovered which means the water is exposed to contaminants and the elements.

Swimming pools also have more bathers which means you need to add chemicals to the water more frequently than you would in a hot tub.

Can I Use Hot Tub Chemicals In My Pool?

You shouldn’t use hot tub chemicals in your pool because hot tub chemicals are not concentrated or strong enough to sanitize a pool. Using hot tub chemicals in a pool will be a waste of the hot tub chemical.

Swimming pools contain more water than hot tubs. They also have more contaminants than hot tubs and experience more action than hot tubs. This means pools need stronger chemicals and more sanitizing than a hot tub does. So adding hot tub chemicals to a pool wouldn’t do much in the pool.

The hot tub chemicals wouldn’t be able to handle the level of contaminants and use of a pool. On the contrary, using hot tub chemicals in a pool will allow algae and bacteria to grow in the pool. This is because hot tub chemicals are not strong enough to protect the pool so the pool is left defenseless against algae and bacteria.

Final Words

Overall, hot tub and pool chemicals might seem, look, and even smell similar but they are very different in terms of concentration and function.

So whatever you do, never use pool chemicals in a hot tub. If you are to do this under any circumstance, you should read the manufacturer’s instructions to be sure the pool chemical can be used in a hot tub too.


My name is Alex and I live in the Northeast of England. I want to combine my love of swimming with my growing knowledge of all things Spa. This site will focus on Swimming, Pools, Home Spas, Saunas, Hot Tubs and any way you can think of to relax and unwind

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