Hot Tub Chemicals vs. Pool Chemicals: What’s the Difference?

Written by: Stuart Lockhart



Time to read 5 min

If you own both a pool and a hot tub, and you run out of hot tub chemicals unexpectedly, you might wonder whether you can substitute pool chemicals for your spa. The short answer is no. Pool and hot tub products may have similar ingredients, but they are different and created for the unique needs of each - the pool and the hot tub. In this article, we look at hot tub chemicals vs pool chemicals. We uncover the difference and why you can’t use them interchangeably.

The Water Volume is Vastly Different

Hot tubs are naturally much smaller than most swimming pools. For example, a hot tub may accommodate two to seven people, while you can fit 20 people or more in a good-sized residential pool.

Because of the size differences, the amount of chemicals you use in a pool or hot tub will be quite different. For example, you definitely don’t want to use the same amount of chlorine, sanitizer, or shock in a hot tub as you would in a pool.

When it comes to water volume, a hot tub may have between 150 and 3,000 gallons of water. Your pool, however, may have at least 25,000 gallons of water. This volume difference means your pool and hot tub have their own unique needs.

Also, your hot tub will go through chemicals at a faster rate due to the ratio of water and bathers. Balancing your water chemistry in each may require different chemicals in different ratios.

While pool and hot tub products have the same components, when you look at the bottles, you’ll notice the concentrations are different.

If you put pool chemicals in your hot tub, you risk sending your water chemistry into a tailspin. Your pH would be off the charts. Conversely, if you added hot tub chemicals to your pool, you wouldn’t be using enough.

The Water Temperature Is on the Opposite Spectrum

During most of the year, your hot tub and hot tub temperatures are very far apart from one another.

Generally, the ideal pool temperature is between 78°F to 85°F. This, of course, depends on the time of year, the weather, and swimmer preference. However, the ideal hot tub temperature is between 90°F to 104°F.

Because of these temperature differences, your pool and hot tub have different needs. Your hot tub, because of the warm water, is the perfect spot for the growth of bacteria, so you need the right sanitizer for your hot tub. In fact, your hot tub will run through sanitizer at a very high rate.

If you try to add a pool sanitizer to your hot tub, you may create an unwanted chemical reaction that is hazardous for your hot tub as well as your soakers.

In addition, pay attention to the calcium hardness levels in both your pool and hot tub. The hot water in your hot tub makes it easier to have calcium issues such as calcium deposits. So, you’ll find that the proper calcium hardness levels for pools and hot tubs are different as well.

Sanitize Your Pool

Introducing poolife NST Prime tablets: the ultimate solution for effective pool sanitization while maintaining water stability. These slow-dissolving cal-hypo tablets work with the poolife NST Feeder or skimmer, destroying contaminants and preventing chlorine loss due to over-stabilization. Compatible with various systems, they ensure unparalleled pool water cleanliness and safety.


The Water Circulation is Different

It’s also important to note that the jets in your hot tub and pool are different, too. For example, your hot tub has a much higher concentration of massaging jets per square foot than your swimming pool.

Yes, your pool does have jets to circulate the water, but the jets in your hot tub circulate the water much faster.

Because of this faster movement, chemical reactions are occurring quickly. If you were to use swimming pool chemicals in your hot tub, you would end up with wildly fluctuating levels in your water balance.

This is just another reason not to use pool products in a hot tub.

The Water Evaporates at Different Levels

Your hot tub water is hot, and the jets are moving the water at a high speed, so naturally you end up with water evaporation. Because of the evaporation, your chemicals become more concentrated.

When you buy hot tub products, they are specially formulated to consider this high rate of water evaporation.

The higher concentration in swimming pool chemicals can actually become “super concentrated” if you use them in your hot tub. You may damage your hot tub equipment and even cause skin irritation for hot tub bathers.

Pools and Hot Tubs Have Different Chlorine Needs

There are some chemical and hot tub products that you need to pay special attention to, and one of those is chlorine.

Your pool and hot tub have different needs. What’s more, chlorine tablets that are made for your swimming pool should not be used in your hot tub because they are too acidic.

If you use pool chlorine in your hot tub, you may end up with a drastic drop in your hot tub’s pH levels. It may take a long time to return your hot tub to the proper balance for hot tub bathers.

Control Your Hot Tub pH

SpaGuard's Spa Sentry, is a pH control product that introduces a buffering compound, simplifying the task of maintaining balanced pH levels in your spa. With just one easy step, Spa Sentry effectively controls the pH for up to two months, providing long-lasting pH stability and reducing the need for frequent adjustments.


The Difference Between Hot Tub Chemicals and Pool Chemicals

Water balance is key, and pool chemicals are not fit for your hot tub, and hot tub chemicals are not right for your swimming pool.

Each one requires different concentrations of chemicals and different amounts.

The bottom line is that your hot tub is not a smaller version of your pool. Your hot tub and pool have different needs, and they need their own unique chemicals.

While the labels on your pool and hot tub products may include the same ingredients, you now know that you can’t use them interchangeably. Yes, the contents are nearly the same, but they are different in the ways that matter. If you tried to use hot tub and pool chemicals interchangeably, you wouldn’t like the consequences for your pool and hot tub equipment and for your bathers.

Make sure you are purchasing high quality pool and hot tub products appropriate for each venue. This way you ensure that you are taking the best care of your pool and hot tub for many years of enjoyment and backyard memories.

Whether you have a hot tub, a pool, or both, you've come to the right place if you're looking for quality pool chemicals and hot tub chemicals shipped to your door. At Pool Goods, we are here for you to help you enjoy every day in your swimming pool with the best pool and hot tub products on the market shipped right to you!