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Hot Tub Start Up Chemicals: How to Open for the Season

Hot Tub Start Up Chemicals: How to Open for the Season
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Hot tubs are an excellent way to sit back, relax your muscles, and destress. However, while hot tubs are known for their relaxing nature, hot tub maintenance can be a scary process to tackle. Learning and knowing what chemicals to use, how to open for the season, and how to properly maintain a hot tub may seem daunting.

Thankfully, hot tub care experts are here to help you every step of the way. We will walk you through everything you need to know regarding hot tub start up chemicals for a successful hot tub season, from understanding why chemicals are essential to an outlined hot tub setup process.

Why Are Hot Tub Start Up Chemicals Important?

In short, hot tub chemicals ensure the water stays clean and clear. If you don’t use the necessary hot tub start up chemicals, you risk bacteria and other germs growing in the water. If this happens, you must drain the water and start over. 

Proper spa chemicals also ensure the longevity of your hot tub. When the bacteria grow in the water, it can cause other tub parts to break down, resulting in unnecessary wear and tear. Show your hot tub how much you care by using the proper hot tub start up chemicals listed below.

Hot Tub Start Up Chemicals You Need

Of course, the first question of hot tub ownership is, “What chemicals are needed for a hot tub?”

Each start-up chemical for a hot tub’s water serves a different purpose. While each chemical has its job in the hot tub water, they all work together to keep your spa water clean and ready to use on-demand. Here are the chemical categories you need to consider as you prepare your hot tub setup.

Products to Adjust pH

The pH levels in your hot tub help control the water’s acidity. If the pH levels are low, there is more acid in the hot tub water than if the levels are high. The more acidic the water is, the harder it is for the sanitizers to do their job, causing higher levels of exposure to harmful contaminants.

Low acidic levels are also prone to corrosion build-up on spa components. This can result in an expensive component replacement. 

Ensure the pH level in your hot tub stays above 7.4 by using a good balancer or pH increaser. You can also test the water using test strips for an accurate reading to see where your water lies on the pH scale. The test strip will tell you where your water chemistry is according to proper levels.

Clorox Pool and Spa - pH Up - 4 pound bag
  • Raises Low pH: Clorox Pool&Spa Swimming Pool pH Up is formulated to elevate the pH levels in swimming pool water. By increasing pH levels, it helps in restoring water parameters to their ideal ranges,...
  • Improves Swimmer Comfort: This product plays a crucial role for swimmer comfort, as it prevents eye and skin irritation caused by low pH. It aids in preventing dry, itchy skin and red burning eyes for a...
  • Protects Pool Equipment from Corrosion: By keeping your pool's pH level balanced, this product helps prevent equipment corrosion, allowing you to spend less time maintaining and more time enjoying your...
  • Preserves Pool & Equipment - Unbalanced water can cause a corrosive environment that damages your pool surfaces or equipment. This product reduces pool maintenance, extending the life of your pool's...


Clarifier chemicals for your hot tub water are designed to clear cloudy water, increase filter performance, and keep a good pH balance. You can use a natural clarifier made from crab and shrimp shells that use flocculation, or you can use a coagulation method that uses enzymes to consume the cloudy particles.

We recommend Clorox Spa Water Clarifier for a clarifier that uses the coagulation method.

Clorox Spa Water Clarifier
6,427 Reviews
Clorox Spa Water Clarifier
  • Combines small particles into larger masses for easy filter removal
  • Makes water crystal clear
  • Safe for all spa types
  • No assembly required

Non-Chlorine Shock

Non-chlorine shock is tasked with oxidizing oils in the water to help reduce strain on the hot tub filters. These oils can come from elements such as perfumes, lotions, deodorants, etc. Non-chlorinated shock is oxygen-based and gives off little odor. 

Using a non-chlorinated shock also means that you don’t have to wait to get back into the water after treatment as it does not contain the harsh materials in chlorinated shock

Our favorite non-chlorinated shock treatment is Spa Depot Oxy-Spa Chlorine-Free Oxidizing Shock.

Sequestering Agent

When the water in your hot tub turns a brown, red, or green color, it is likely due to calcium or heavy metal build-up. Using a sequestering agent will help remove that excess calcium and heavy metal. If you notice the water in your hot tub changing colors, consider using Spa Choice Bromine Booster to help combat the build-up.

Spa Choice Bromide Booster Spa Sanitizer
427 Reviews
Spa Choice Bromide Booster Spa Sanitizer
  • Establishes a quick bromide reserve in spa water
  • Use with bromine tablets
  • Add 1/2 ounce of product per 100 gallons of spa water to establish a 30 ppm (parts per million) bromide reserve before using bromine tablets


As with other sanitizers, a hot tub sanitizer kills unwanted bacteria and helps purify the water. Sanitizing your hot tub is considered one of the most crucial steps of spa maintenance as it helps keep occupants safe from harmful bacteria.

Consider using the Aqua Clarity hot tub sanitizer for best results. 

Aqua Clarity Hot Tub Cleaner
122 Reviews
Aqua Clarity Hot Tub Cleaner
  • 3 in 1 Hot Tub Maintenance Chemical: Aqua Clarity LOVES Hot Tub & Swim Spa Water. Aqua Clarity functions as a water enhancer promoting that soft and silky feel, a water clarifier to enhance and improve...
  • Most Effective Water Clarifier: Water is precious. Why dump it so often? Plus, sanitizer demand rates will generally be reduced. Less sanitizer can mean a more refreshing soak in more natural water. Aqua...
  • Easy Usage: It'll keep the water, plumbing and jets clean & clear. Save on Plastic Program. Let the magic begin with the 'just add water' concept. Simply mix the Aqua Clarity with water according to given...


Outside elements such as oils, lotions, and cosmetics can cause your spa water to foam. Because of this, using a defoamer in your hot tub start-up process is a must. Just as the name implies, the defoamer eliminates foam from generating. 

Use Leisure Time 302414A Foam Down Cleanser to defoam your spa water. 

Leisure Time Foam Down Cleanser for Spas and Hot Tubs
4,050 Reviews
Leisure Time Foam Down Cleanser for Spas and Hot Tubs
  • BENEFITS: Stops and retards foaming in hot tubs and spas
  • USE: As needed to stop unsightly foaming; shake well before using; add Foam Down directly to the foaming area using approximately 1/2 oz. at a time
  • COMPATIBILITY: Chlorine, bromine, ozone and biguanide sanitizers
  • FEATURES: Easy to use defoamer; begins working immediately


Ensuring your hot tub water has proper calcium levels is vital to the longevity of your spa. Keeping the calcium levels up helps prevent corrosion or scaling in your hot tub. This corrosion spreads to the fittings and other vital components, preventing them from performing properly. 

Try using AquaDoc Spa Calcium Hardness Increaser as a calcium hardness additive for your hot tub. 

AquaDoc Spa Calcium Hardness Increaser
356 Reviews
AquaDoc Spa Calcium Hardness Increaser
  • Make balancing your water easier & more cost effective with AquaDoc's calcium hardness increaser. Our spa calcium hardness increaser is vital to ensuring proper water hardness levels in your hot tub....
  • Avoid corrosion, etching, and staining - AquaDoc's Professional Grade Hot Tub Calcium increaser is your best defense against soft water in your hot tub or spa. Guard calcium levels from decreasing too low...
  • How it works - AquaDoc's Hot Tub Calcium hardness Increaser works to raise your water's hardness level to ensure properly balanced hot tub water. Our spa hardness increaser easily works to raise your...


Sometimes balancing water when opening a hot tub is necessary. Balanced spa water has proper alkaline and acidity levels. When spa water is properly balanced, it allows your sanitizer to work as it should and makes the water feel more pleasant on the skin. Conversely, if your hot tub water is not balanced, you may experience water that feels hard on your skin and is more prone to bacteria. 

Consider using Silk Balance Natural Hot Tub Solution as a spa water balancer. 

Silk Balance Hot Tub Solution
61 Reviews
Silk Balance Hot Tub Solution
  • Great Hot Tub Water Experience - silk balance natural hot tub solution 76 oz chemical leads the way in premium spa water care with a unique, unmatched, proprietary formula specifically designed to...
  • Great Water Made Easy - You will now have more time to enjoy your silk spa and spend less time playing chemist. Silk Balance is specially formulated, without harsh chemicals, to be self-adjusting. Even the...
  • Environmentally Friendly Natural Solution - silk balance for spas is safer and easier on the environment than the harsh chemicals currently used in the water care maintenance of spas. Silkbalance...

How to Set Up a Hot Tub (12 Steps)

Setting up your hot tub for the season can be completed in 12 steps. While they may not seem glamorous, these steps are necessary before you can enjoy a long soak in your hot tub. Pay special attention to chemicals needed for hot tub use.

1. Rinse and Drain

Rinsing and draining your hot tub is the first step you have to take before you can enjoy the upcoming hot tub season. Ensure you drain the water into an area that won’t cause a soggy mess in your yard. Otherwise, you may have another outdoor project to complete. 

If you’re a new hot tub owner, you get to skip to step 4 for the first time setup

2. Turn Off All Power

While the power does not have to be off to set up your hot tub, it is recommended. Turning off the power ensures your safety by preventing shocking mistakes or accidental power-ups. To ensure all power is off before beginning, switch off the spa equipment and unplug the tub. 

Water and electricity don’t mix. That is why it is better to be safe than sorry in this situation.

3. Clean the Empty Hot Tub

One of the most vital steps of the setup process is cleaning the empty hot tub. As with a bathtub, you don’t want to soak in bacteria or last year’s gunk. 

If you have a new hot tub, you want to remove any outside dirt and grime before adding water. Then, spray and wipe down all surfaces with a soft cloth and a non-abrasive cleaner to prevent any damage but still clean the surface. 

If restarting your old hot tub, you may consider performing a deep clean.

Spa & Hot Tub Surface Cleaner Spray
  • Strong, Fast Acting Spa Surface Cleaner - Say goodbye to dirt, grime, scale, and scum lines. Simply use our spa tub cleaner to easily wipe off any dirt or stains appearing on the surface of your jacuzzi or...
  • All-Purpose Hot Tub Surface Cleaner - Our formula is a pool surface cleaner, bathtub surface cleaner, jacuzzi surface cleaner, and works on luxury baths or above ground pool cleaning. Easily use our hot...

4. Install or Clean the Filter

To ensure your hot tub stays clean, you will want to install a new filter or clean the old one. The filter plays an integral role in spa maintenance and is a must to ensure hot tub longevity.

5. Fill Your Hot Tub

It’s time for the fun part! The next step is to fill your hot tub. Using a garden hose or tap water, begin to fill up your hot tub while keeping an eye on the water levels. Because water can contain impurities that will counter the chemicals used to combat bacteria in your hot tub, we recommend using a hose filter during this step.

A hose filter will help keep unwanted minerals out of the water, making it easier for the jacuzzi chemicals to do their job. If you don’t have a hose filter, place the end of the house near the filter system in your hot tub so the minerals are removed efficiently.

Ensure the water level does not get too high. A general rule of thumb is to fill the spa up to around an inch below the headrest but still cover the jets. This ensures water does not spill out when the hot tub is in use.

6. Prime the Pump

Air can get stuck in the hot tub lines, which can cause issues down the road. Priming the hot tub pump ensures there is no air in the lines helping prevent these future issues.

Consult your owner’s manual to prime the pump, as each hot tub has a different process.

7. Add the Start Up Chemicals

It’s not time for the step we’ve all been waiting for, adding the spa start up chemicals. Several measures need to be taken before adding the chemicals to the hot tub. First, ensure the water has reached 80 degrees Fahrenheit before adding chemicals to the hot tub for the first time. This ensures they dissolve and infuse into the water.

Next, determine how much water your hot tub holds. Knowing how much water is sitting in the spa will help you understand how many chemicals to use. Then, measure your chemicals accordingly. Refer to a hot tub chemical chart to make sure measurements are exact and accurate.

Finally, pour the chemicals according to the instructions into the water and begin the hot tub water treatment. Chemicals for hot tub startups are very important for the health of your spa.

8. Run the Pump

Once your chemicals have been added to the water, run the pump on high for ten to fifteen minutes. This ensures the chemicals are evenly distributed throughout the water, and you get an accurate test result. 

9. Test Your Water

Testing the water ensures you have the correct chemical levels to ensure user safety. If the chemical levels are off, it can cause skin irritation, damage to the hot tub, and expose users to bacteria.

10. Set the Water Temperature

Based on your personal preference, set the water temperature. The recommended hot tub water temperature is between 98 and 102 degrees Fahrenheit. Whatever you set your water temperature to, ensure to keep it consistent. If you reheat the water for every use, you risk stressing the heater and circuit board and increasing your electric bill. 

11. Cover Your Hot Tub

After you set the temperature, let the water circulate for another ten to fifteen minutes, then put the cover on. Keeping the hot tub cover on when not in use helps maintain the heat and keep the water in the hot tub. 

Check out the best hot tub covers!

12. Test Your Water

Didn’t we already mention testing the water? Yes, we did. Testing the water after it has stabilized will give you a more accurate chemical level reading and inform you if you need to make adjustments. 

Digital Water Test Kit for Hot Tubs
856 Reviews
Digital Water Test Kit for Hot Tubs
  • Features a photometer which gives you a digital reading of test results.
  • Water resistant housing and carrying case provided.
  • Tests Free Chlorine, Total Chlorine, Bromine, PH, Alkalinity, Calcium Hardness, and Cyanuric Acid.
  • Uses liquid reagents for all test factors except Cyanuric Acid, which uses tablets.

Additional Considerations Before Restarting Your Hot Tub

When your hot tub sits with no use during the off-season, it is prone to wear and tear. Before restarting your hot tub, check for any cracks, stains, or mildew and address them accordingly. 

You may also consider checking the wiring. For example, ensure there are no frayed or loose cords. If so, call an electrician to address the issue. 

Hot Tub Start Up Chemicals FAQ

How Soon Can You Use Hot Tub After Adding Chemicals?

Wait at least two hours before using your hot tub when you add chemicals. This allows the chemicals to activate and begin working and also ensures the chlorine levels are safe for use.

How Much Chlorine to Add to Hot Tub First Time?

When filling your hot tub up for the first time, you want to use a high chlorine dosage to ensure it is properly sanitized. Start by adding 60g of chlorine per 1,500 liters of water. Before using the hot tub, ensure the levels have dropped to 3-5mg per liter. 

Do I Need to Put Chemicals in My Hot Tub Right Away?

Unlike a bathtub that you fill and immediately drain, the water in a hot tub sits for weeks and even months on end. If you let the water sit without adding chemicals, you have created a breeding ground for bacteria and other organisms that can be harmful. 

When Can I Add Chemicals to My Hot Tub After Filling?

Wait until the spa is full and the water has reached 80 degrees Fahrenheit before adding your chemicals. The heat helps the chemicals dissolve and effectively incorporate into the water. 

How Do You Shock a Hot Tub for the First Time?

Make sure all blowers are off, and the water is calm. Then, measure the shock according to the amount of water and safely pour it into the water. Leave the hot tub uncovered for 20 minutes to allow the shock to disperse.

Should I Adjust Chlorine, Alkalinity, or PH First During Hot Tub Set Up? 

Ensure the total alkalinity is correct before adding additional chemicals to your spa water during the hot tub setup. Setting the right alkaline level will help you properly adjust the pH and chlorine levels. 

Starting Up Your Hot Tub is Easy!

Whether you’re a seasoned hot tub professional or you’re starting up your first hot tub, using the proper hot tub startup chemicals is essential. Not only do the chemicals provide comfortable and pleasant water for users, but they also ensure the longevity of your hot tub. 

Pricing on this page was last updated on 2024-05-27