Hot Tub Chemicals guide for beginners


Owning a hot tub or swim spa must be exciting for you. You go to your nearby hot tub dealer, browse for the best hot tub, select one, and land a deal with the seller and ta-da! You have the best hot tub at the perfect location at your house, but what you fail to think is the hot tub water chemistry involved.

Hot tub chemistry

Buying a hot tub is easy, but maintaining the very same hot tub is not that easy. That said, you don’t need to scratch your brains or get a degree in chemistry. All you need is the right chemicals and a hot tub and let the magic happen.

Maintaining a hot tub is necessary because, unlike your bathtub, you don’t drain the water every time you use it. The water in your spa stays there for weeks and months to come, and you must know very well that stagnant water always becomes unclean and filthy.

But, do I really need chemicals for my hot tub?

The answer is YES! You really do need hot tub chemicals to maintain and sustain the longevity of your spa. If you want to submerge yourself in the spa regularly and enjoy some me-time or have a relaxing time with your friends, you definitely need to balance the water chemistry level!

There is no way that you can avoid using hot tub chemicals. Filthy water, which is filled with germs and bacteria, will not only damage the equipment of the hot tub but also give you hot tub related illnesses. Stagnant water and an unbalanced chemistry level will become a breeding ground for various organisms. The key to avoiding spending a hefty amount in the near future for the repairs of your hot tub is to have your hot tub water chemistry balanced.

Which Hot Tub chemicals do I need?

Hot Tub chemicals

The answer to this question about which chemicals do you need or how much of it you need is to test the water first. Make sure that you have testing strips to test the water so that you know how much proportion of chemicals you need to add to level the chemical balance. Once you get a proper reading, you can start adding chemicals until you get the desired chemical level.

The major chemicals you will most likely need are:


Maintaining a sufficient level of sanitizer is very crucial. Sanitizers are used as a disinfectant against various pathogens and purify the hot tub water. The sanitizers used by most hot tub owners are:

  • Chlorine
  • Bromine
  • Minerals
  • Biguanide
  • Salt system

Chlorine is the more potent and most commonly used among the sanitizers. Chlorine is more pocket friendly and more effective on germs. Chlorine can be added either by putting chlorine granules in the water or diluting it in warm water and pouring it in the hot tub water. You can also use chlorine tablets, which can be added to the floating dispenser. Always start by using a low amount of chemicals to avoid overdosing.

Bromine is another alternative sanitizer. The advantage of using bromine is that it has a low pH level than chlorine, but it is more expensive than chlorine. Another benefit of using bromine is that it lasts longer and is also mild on the skin. Bromine also takes time to affect the water.

The proper level of chlorine and bromine should be maintained in the water; 2-4 ppm of bromine and 1-3ppm of chlorine.

For a more effective method, you can use minerals along with chlorine. Silver and copper, which is known as bactericide and algaecide, respectively, can be used as active ingredients. Minerals are easy to manage compared to chemicals. Unlike other sanitizers, they already are available in the correct dosing proportion, so you don’t have to measure it and wait for it to work in the water.

Another sanitizer is biguanide. Albeit it costs more than chlorine and bromine, it doesn’t have to be used very often and makes the water very smooth for the next use. Before using biguanide, consult your hot tub dealer, as it is known to damage the plastic in the hot tub.

Salt systems are newly introduced in many hot tubs nowadays. It is considered very cheap in comparison with chlorine. The hot tub converts the salt into chlorine, and it has the same water effect. This saves your bucks from buying chlorine.

Hot tub sanitizer

Shock is also a type of sanitizer available in the market. It sanitizes your tub more than any other sanitizers. You can use it after you use your usual chemicals as the shock is known to kill bacteria, which your regular chemicals may have missed out. It comes in both chlorine and non-chlorine form.

Spa shocks are used for various water issues; it can also remove foul smell and discoloration of water.  Spa shocks can sound aggressive, but what it does is oxidizing contaminants and releases them in gas form. Using this method can help you decrease the usage of a high dosage of chemicals in the water. When you drain and refill your hot tub, it is recommended that you use sodium dichloro, which is a sanitizer, as well as shock.

Before using any chemicals, make sure to read the label to ensure that you’re using the right dosage of chemicals, to avoid anything dangerous if it is messed up.


Cleaner products are used to clean the flush lines to remove the biofilm. You can use it to clean the surface of your hot tub, spa shell, and spa cover. Avoid using household chemicals to evade any possible damage to the hot tub. Cleaners are also used to clean the plumbing lines so that the water doesn’t get filthy. Make sure to use cleaners once a week for a better effect.


Hot Tub Clarifier

To make your water look crystal clear, you need to use clarifiers. Clarifier chemicals are generally used for spa filters or when water is cloudy. Clarifiers don’t clean the problem from its root, so it is better to use chemicals along with the clarifiers. Clarifiers act as polymers and attract themselves to particles floating around in the water.


You get the correct water chemistry balance only by using the right amount of chemicals. Total alkalinity, pH level, and the calcium hardness should be within the acceptable ranges. The pH level of water should be from 7.2 to 7.8, the ideal being 7.4 to 7.6. Total alkalinity should be at 80-120ppm, and calcium hardness should be within 150-250ppm. You can increase or decrease the pH level with a pH increaser or decreaser accordingly.

When and how do I put chemicals in the hot tub?

The first step is to remove the hot tub cover. The hot tub must be kept open during this time as when the chemicals are put in the hot tub; they release gas.

After this, you need to switch on the spa and let the water circulate the chemicals in the hot tub for it to mix well. But make sure to switch off the air jets as some chemicals wouldn’t work properly if exposed to air spray.

After you let the water circulate the chemicals for some time, take test strips and insert the strips in the water to check the pH, alkalinity, and calcium hardness level before you try to balance the water chemical level.

Remember to wear gloves when you pre-measure the chemicals and pour them. Sprinkle the substances in the water and let it circulate for 15 minutes. Keep the cover open for the chemicals to breathe appropriately.

Which are the Natural hot tub chemicals?

If you want to take another approach to balance your water chemistry level, you can use hot tub mineral sticks that already come in the right dosage form. These sticks use silver and copper ions to purify the water.

Natural hot tub chemicals

Another method is to use ozone, which is injected through the Ozonator (ozone generator) into the plumbing of your hot tub; this is a way of natural purification of the water without using high usage of chemicals. Along with destroying bacteria and algae, it also oxidizes other contaminants. Ozone improves the performance of chemicals like chlorine and bromine and other sanitizers. To learn more about Ozonator, you may read our spa Ozonator reviews here.

You can also remove organisms by using enzymes, which are natural dirt eaters. But enzymes cannot alone be used to purify the water without adding chemicals like chlorine and bromine.

The best way to know which chemical is best suited for you is to try it.

hot tub chlorine and Bromine

Chlorine is inexpensive, works effectively on algae and bacteria. It kills organisms faster than any other sanitizers. The downside of using chlorine is that it is harsh on the skin, eyes and hair. Also, it is known to even trigger asthma attacks in some people.

Bromine is expensive compared to chlorine; the effect of bromine lasts longer than chlorine. Bromine has a low pH level, so it takes longer to work on to clear the contaminants. Bromine is -gentle on the skin, but it would take you longer to rinse it off from your body. Bromine, unlike chlorine, cannot remove all contaminants and keep the water crystal clear.

To make an educated decision, you need to be aware of the effects of the chemicals, and you can find this by using both of them one after the other to purify the water.

Remember: Never mix chlorine and bromine together in your spa water unsupervised as this can have a hazardous chemical reaction.

You can switch from one chemical to another after you drain and clean your hot tub.

Are these chemicals harmful to me?

Hot tub chemicals safety

Well, so to speak they are chemicals on the one hand, but one can’t live without using them too.

Chlorine and bromine are sanitizers which work great in your hot tub, but both have adverse effects on your skin. Chlorine is known to cause skin irritation and dry and will damage your hair. Chlorine is known to remove all your body’s natural oils and exposing your pores to chemicals. Prolong stay in chlorinated water can cause rashes on your skin.

Although bromine has a low pH level than chlorine, it is also known to cause skin issues. It can cause redness and irritation in your eyes too. Both chlorine and bromine can cause respiratory problems in people.

How are you able to reduce the effect of these chemicals on your skin? Well, the primary thing to do is to limit your contact with these chemicals.

The other ways are:

  • Shower before and after every use of your hot tub.
  • Change your water at recommended intervals
  • Shock your hot tub after every use.
  • Clean and change the filters regularly.
  • Keep the hot tub cover closed after every use.
  • Check the pH level of water daily.
  • Use the only recommended amount of chemicals for your hot tub.

Maintain a schedule or calendar to remind yourself to clean your hot tub at regular intervals.

In conclusion, chlorine and bromine, when used in moderation, will thoroughly sanitize your hot tub and is safe for you too.

Hot Tub Chemicals FAQs

How soon can I use my hot tub after adding chemicals

Well, it depends on how much amount of chemicals you have put in your spa. It can take anywhere from 3 hours to 24 hours. The safe way is to use your spa after 24 hours

From where should I buy hot tub chemicals in bulk?

You can buy chemicals in bulk from your nearest wholesale store or any online stores.

Which hot tub chemical is safe to use?

The decision depends on you. Each chemical has its advantages and disadvantages, so it’s a ‘toss a coin’ situation. You can select one after trying it once and choose according to your preference.

When should I drain my hot tub water?

If in case, you don’t reach your desired chemical balance, you can drain, clean, and refill it. Otherwise, you should always drain your hot tub water quarterly.

Is it okay to add fragrance to the hot tub water?

Yes, it is safe to add a scent or a fragrance to the water, but make sure to avoid oil-based fragrance. You can go for a water-based fragrance to add in the water.

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