What Spa Chemicals to Use?

Keeping your hot tub clean is simple as long as you know what chemicals to use. You may be wondering which ones are safe and when do you add them. Some may want to know the right amount to use in their hot tubs.

It may not seem very clear, and you may be tempted to call the professionals, but it can be easier than it looks. Once you get a good handle on how and when the treatments are added, keeping the water clean and safe can be easy.

Do You Need the Chemicals?

Yes, you do. These hot tubs are not the bathtubs that you drain and fill. This is the same water you’re using for months, and you need the right natural spa chemicals to keep it sanitized and clean. Without the right treatments, you may find it an excellent place to incubate microorganisms and critters, primarily if the tub is located outdoors.

You may be thinking of vacuuming once a week to keep the debris and leaves out. However, this is not enough as you may experience equipment failure, illnesses, and a lot of clean-up work without the chemicals.

What to Use?


Chlorine is one of the most common owners’ choices as it can kill algae, fungi, bacteria, and viruses. It’s easy to add and manage as well as it’s cost-effective. One of the drawbacks that many have found when using chlorine is that it smells terrible.

Know that it’s not the actual chlorine that smells in your spa tub but the chloramines. The bacteria and viruses are killed by the process of oxidation that breaks off their cell walls and other organic chemical components. As this chemical reaction occurs, the waste products like chloramines can give off “that smell” related to chlorine.

If the water is smelling bad, you can shock your hot tub to bring the chlorine back to a higher level. You should remove the chloramines and put them back to work in killing the remaining microorganisms. Learn more about the importance of chlorine on this site here.


This is a non-chlorine sanitizer. It essentially kills bacteria, and you don’t have to use it, usually unlike chemicals like bromine and chlorine. At every stage in the sanitation process, it’s practically odorless, and the water can feel smoother to the guests of the hot tubs.

However, biguanide has a downside because it’s more expensive than chlorine. It may cause a rapid deterioration in some parts like plastics and rubber gaskets. You should check with an expert before using this chemical in your spa.


Copper and silver are two of the most common minerals that many experts use. Copper is known to kill algae, and silver is a bactericide. They are an active ingredient that will not let you use too much chlorine.

This means that you don’t have to deal with harsh water for your skin. The minerals alone may not be enough to do total sanitation, so you may want to supplement this with other chemicals for a complete treatment.

Notice that using minerals like silver as a means for using use less chlorine and it doesn’t mean no chlorine at all. Know more about silver as an antimicrobial here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6315945/. These are the less expensive solutions, and you won’t have lesser problems with nasty smells because of the absence of chloramines.

You can easily manage the minerals, and you don’t have to measure them when you add them to your hot tub. Some are available in dosing sticks that you add into your filtration systems every four months. Ensure that you’re following the manufacturers’ instructions when using these for your and your family’s safety.

Salt Systems

Saltwater pools are common in many homes today, and they are trendy in hotels too. If you want to feel like you’re at sea, a saltwater hot tub can be a more convenient option for you—an addition of a salt-chlorine generator to give you a seaside vibe.

As mentioned, these salt systems still use chlorine as a way to sanitize the water. Some may change their water completely every 4 months to reduce the buildup of shampoo, sweat, and body oils. In the meantime, if you’re noticing that it’s not yet too foamy and the water is not yet discolored, the chemicals will still do the trick, and this can be an effective way of sanitizing everything.

Check the acidity levels, alkalinity, and other factors to make sure you’re relaxing on safe and clean water. The generators in these systems may convert salt into chlorine, so this can be a less expensive alternative. Also, the water will be a lot gentle for your skin, hair, and eyes, so you may want to try this kind of system if it works for you.

Test strips that are for saltwater are often effective. The proper chlorine levels should be one ppm to 3 ppm, just like the ones in spa tubs. Salt levels should be around 2,500 ppm in an ideal situation.