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Spa & Hot Tub Chemicals

Whether you’re spending the afternoon relaxing with friends or enjoying a solo soak under the stars, we have all the products you need to keep your hot water oasis in peak condition. Our selection of spa and hot tub chemicals spans a full selection of balancers, sanitizers, conditioners, and natural, enzyme-based options. Stop by your local superstore today to find the right regimen for your spa style and budget.

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What Chemicals Do You Need for a Spa?

You’ve finally purchased the hot tub of your dreams and found the perfect location for it. You might be eagerly waiting for the right moment to climb in and relax. First, make sure you have the essential component that every hot tub owner needs: hot tub chemicals. 

Like a swimming pool, managing hot tub chemistry is simple once you understand the right chemicals and treatment that go into your hot tub water. Maintaining the chemical balance includes checking pH levels, alkalinity, sanitizers and shock treatments.

Don’t worry: You don’t need a degree in chemistry to know how to keep the water clean in your hot tub. Fortunately, Watson’s can help you become an expert on maintaining your hot tub. Participating locations even host free spa classes to walk you through the process.

Guide to Spa Chemicals and Other Cleaning Tools

Below is a short guide to the spa chemicals that owners commonly use to clean their home hot tubs & spas. 

Metal-Free Spa Chemicals

Those who are reopening their hot tubs or filling them up for the first time should let the spa water circulate for about an hour. Using metal-free spa chemicals is perfect for neutralizing any metals that are in the water before any other chemicals are adjusted. Metal neutralizers circulate for about 4-6 hours before you move on to the next chemical treatment.

Spa Test Strips

Take a sample of the spa water with test strips to determine its current chemistry. A few of the most common chemicals that are tested in a spa test kit include chlorine/bromine, pH, alkalinity and calcium hardness.

Testing and adding the proper amount of chemicals to spas is imperative to stay within the recommended ranges for balanced water in your hot tub. Once you get a solid reading on your water chemistry, pour calcium harness, followed by a pH balancer and sanitizer.

Calcium Hardness

Calcium hardness is the amount of magnesium and calcium dissolved inside your hot tub water. Measuring calcium hardness is one of the best ways to know how much calcium is in your water. When calcium hardness levels are too low, your spa may be susceptible to damage and erosion. Make sure you add calcium hardness to your water so it becomes leveled at the perfect soft water range, avoiding any possible damage.

Alkalinity and pH

Total alkalinity and pH work closely together in spa chemistry. Alkalinity measures the amount of carbonates and bicarbonates inside your hot tub, which acts as a buffer to stabilize pH in water. Essentially, pH measures the acidity in your hot tub water. 

When the pH of your hot tub is below 7.0, the water becomes corrosive and can damage your spa’s internal system. If the pH is above 8.0, stains and cloudy water can begin to form. A high pH might also mean that too much calcium is present and can be visible on the spa’s surface and inside its pipes. 

When the alkalinity is below its recommended range, it causes the pH in water to change levels frequently and become unstable. If the alkalinity is too high, this causes the pH to be resistant to change. 

Chlorine or Bromine

Many people recommend bromine treatment, as it holds up better under heat and can be a more effective sanitizer over time when compared to chlorine. One downside to bromine is that it can be a higher price. This is worth it, though, as bromine kills bacteria and viruses in hot tubs without leaving an odor or unpleasant scent. Bromine is also less likely to cause irritation to the skin compared to chlorine.

Shock Treatment

One of the most important components of maintaining spa water is to shock it. Shock treatment is necessary when you’re opening your hot tub after a long period of inactivity or after heavy use, like having a party with several people in the tub. It is imperative that you shock the spa water to keep it safe and free from contaminants. Here’s what a shock treatment does:

  • Kills bacteria. Shock treatment easily kills bacteria that live inside your spa water.
  • Removes bromamines and chloramines. Treatment breaks down the bonds and contaminants that form inside your hot tub.
  • Removes organic compounds. The level of organic compounds can spike if you have a lot of people in at once. Removing these compounds is crucial to keep water clean.


Fragrances are not necessarily needed, but are a nice option to create a more spa-like atmosphere. There are many kinds of aromatherapy scents that are specifically made for hot tubs. Their scents come in a wide variety of options and make a great addition to a relaxing hot tub. 

Hot Tub & Spa Treatments

We hear owners ask: Do I really need to use chemicals? Yes, you need to treat your water to ensure that it’s safe, healthy, and uncontaminated. Without the right chemicals, dangerous microorganisms and unsightly hot tub foam can develop. Finding the right combination of chemicals can take trial and error. Fortunately, Watson’s has everything you need to properly clean your hot tub or spa. Browse our selection of chemical treatments, and contact a customer service representative for additional guidance and information today.

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  • What are the essential hot tub chemicals?
    • Essential chemicals for hot tub water care include a hot tub sanitizer like chlorine, alkalinity increaser, pH increaser, pH decreaser, and calcium hardness increaser. Brands like Spa Frog offer a wide selection of mineral purifiers, test strips, and other water chemistry supplies.
  • What is the safest hot tub chemical?
    • While no spa chemicals are safe enough to ingest in high quantities, bromine is safer to use than chlorine and is less irritating to sensitive skin.
  • Is it possible to use a spa without chemicals?
    • You shouldn’t use a spa without chemicals. Untreated water can quickly cause harmful algae and bacteria growth, hot tub rash, foam development, and can even ruin hot tub equipment.
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