What to After a Hot Tub Refill: Informative extra steps after a hot tub refill

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After a Hot Tub Refill: Informative Extra Steps

Keeping your hot tub clean and filled with fresh water is key to an enjoyable spa experience. One important part of hot tub care is refilling the water every 3 months, but the frequency also depends on the intensity of use. Learn how to drain and refill your hot tub correctly and what extra steps you need to take after refilling in this blog and accompanying video.

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Draining and refilling your hot tub water needs to be done regularly. That's because the water in your hot tub can easily be saturated due to organic material entering the water. This organic matter can consist of many different things such as skin, fats, and oils but also calcium or sand and many more. At some point, the hot tub chemistry water will become challenging to handle.

  • After you refill the hot tub, start with the water balance.
  • pH level is a significant factor concerning water balance.
  • pH level will let you know how acidic or basic the water is.
  • The pH level should be between 7.2 and 7.6 otherwise, sanitizer can’t kill bacteria effectively… Adjust it up or down using pH + or pH -
  • ‍Add a Sanitiser and test the water again.

Why does hot tub water need to be renewed?

‍Hot tub water needs to be renewed for two reasons: to prevent bacteria and keep the water clean. Bacteria can grow rapidly in moist conditions, and hot tubs provide the perfect environment for them to thrive.

If the water is not regularly replaced, the bacteria can build up to levels that are harmful to human health. In addition, hot tubs are used by many people, which means that the water can quickly become dirty.

Regular renewal helps to ensure that the water is clean and clear. While it may seem like a lot of work, renewing the water is essential for maintaining a safe and enjoyable environment.

Water filtering accounts for 50% of spa water sanitation.

On average, change filters at least once every year and make sure your water is not too old, so you avoid saturation.

On average, you need to replace the water every 3 months, but it also depends on the intensity of use.

How do I know when to replace my hot tub water?

There are a few telltale signs that it's time for fresh water:

  • The water looks cloudy or dirty
  • The pH levels are off
  • You can see or feel the grime on the sides of the tub or the jets
  • The smell of chlorine is strong

If any of these things happen, it's time for a change! Luckily, spa drains and refilling your new hot tub is relatively easy. Here's how to do it:

How to drain & refill hot tub

As a hot tub owner, you know that refilling your hot tub is an important part of spa maintenance. Let's cover all the steps that will apply to most hot tubs.

1. Turn off the hot tub power

Turn off the power to your hot tub at the circuit breaker box. This is an important safety precaution!

2. Drain your hot tub

Find the drainage valve and open it up so the water can start the hot tub draining out. While the water is draining, you can use a hose to spray down the tub's sides to remove any dirt or debris.

3. Clean the inside of your hot tub

Once the water has drained out, close the drainage valve and give the tub a good cleaning with soap and warm water. Be sure to pay extra attention to scrubbing any areas where dirt or grime has built up (like on the jets).

4. Rinse your hot tub out

Rinse the tub with clean water until all traces of soap are gone. You can also add any new chemicals you want in your diluted form (more on that later).

5. Refill your hot tub

Now it's time to start filling up your hot tub again! Attach a garden hose to a faucet and let 'er rip until the tub is full again. Ensure you leave enough room at the top so that when you turn everything back on, there's no chance of overflow.

Once you've reached your desired level, turn off the hose and reattach any panels or covers you removed during step one.

6. Add hot tub chemicals

The final step is adding chemicals back into your newly filled hot tub! You'll want to add them in their diluted forms not to shock your system. Add chlorine last because it will disinfect everything else in your system as it circulates.

If everything looks good, go ahead and turn your power back on at the breaker box and enjoy!

What extra steps do I need to take after refilling my hot tub?

It's important to refill your hot tub regularly to maintain a safe and enjoyable environment. In this section, we will cover all the steps that apply to most hot tubs, from draining the water to adding chemicals. So read on for all the info you need to know!

For everything to run smoothly, there are a few extra steps you'll need to take after filling up your newly cleaned hot tub:

1) Check all filters and clean or replace them if necessary

Filters play an important role in keeping your spa water clean and clear. They help to remove debris, dirt, and other impurities from the water, which can cause problems like cloudy water or bacteria growth. It's crucial to check your filters regularly and clean or replace them as needed to ensure that your spa water is always safe and enjoyable.

It's also important to note that dirty filters can be dangerous. If not cleaned or replaced regularly, they can quickly become clogged with dirt and grime. This can cause the submersible pump to work harder than it should, leading to overheating and even fires. So make sure you're taking good care of your filters by checking them often!

Filters offer several advantages for hot tub maintenance, including:

  • keeping the spa water clean and clear
  • preventing debris buildup
  • reducing the need for chemical additions
  • helping extend the life of the pump

2) Inspect all hoses for cracks or leaks

After you've refilled your hot tub, it's a good idea to check all the hoses for any cracks or leaks. These can be dangerous as they allow water to escape and cause electrical problems.

Alternatively, you can invest in a hose cover to prevent any cracks or leaks from happening in the first place.

3) Test pH levels and adjust accordingly

Check the pH value and correct it if necessary by using pH + or pH -.

The pH level should be between 7.2 and 7.8 to ensure that any sanitizer, like chlorine or bromine, can work properly.

This pH level will also ensure that the water will not harm the equipment.

4) Balance alkalinity levels

The alkalinity level should be between 80 and 120 ppm (parts per million).

This ensures that the pH levels stay stable and prevents equipment corrosion.

Let's understand how is the alkalinity level important for the hot tub.

The alkalinity level in a hot tub is important because it affects the pH levels. Alkalinity is a measure of the water's ability to neutralize acids. If the alkalinity level is too low, the pH level will be unstable and could drop quickly, leading to equipment corrosion. If the alkalinity level is too high, the pH level will be difficult to adjust.

5) Sanitation & shock treatment

Next, you should check what to do with the sanitizer.

The most commonly used are chlorine and bromine.

Important to know is that you want to know what the FREE chlorine level is because this is the chlorine that can still kill off contamination….Measurements for total chlorine or combined chlorine can be important, but there is a difference.

We will explain further, but most test strips will only show "free" chlorine, so you can start by correcting the value.

Add sanitizer (chlorine or bromine) to get ideal free chlorine between 3-5 ppm, or ideal bromine between 2-6 ppm.

Chlorine will work quickly and bromine takes more time to work.

  • To raise the level by 5 ppm in a 1500-liter hot tub you need to add about 15 grams to start.
  • To raise the level by 5 ppm in a 396-gallon hot tub, you need to add about 0.53 ounces.


It is always difficult to advise in absolute numbers because different types of chlorine and different brands of chlorine can vary in the amount of active substance, so always check yourself after mixing it.

Check your work after mixing and see if the pH and chlorine/ bromine levels are good.

6) Check & calibrate if needed

After adding the sanitizer, you should check and calibrate your pH levels. The ideal pH level is between 7.2 and 7.8.

You can use a pH test kit or strips to check the levels and adjust accordingly.

If the pH level is too high, you can add a pH- reducing agents like muriatic acid or sodium bisulfate.

If the pH level is too low, you can add a pH- raising agent like sodium bicarbonate or baking soda.

7) Add O-Care

When and if you add O-Care, the water can get cloudy…don’t worry that means it is working, and it will clear up soon. Often in minutes, but depending on the water quality, it can also take hours.

I hope and assume the water is clear and all you “need” to do now is add O-Care, and you’re ready to go

After taking care of all these things, your newly refilled hot tub should be ready for action!

But if not:

  • If not just repeat what you just did however if you keep changing the pH and you can’t set it than read this.
  • If your chlorine levels keep fading away and you can’t measure free chlorine, then click here
  • If the water is not clear or you are experiencing any other issue, then click here

Next steps for superior water that only hot tubs provide

At O-Care, we care about providing the best Hot Tub experience regardless of the system you use. Of course, we highly recommend enhancing your water quality and decreasing your maintenance costs by utilizing O-Care. Find your local dealer who can deliver O-Care to your doorstep.

Additional Resources to keep your hot tub clean

  1. Download the O-Care app for weekly maintenance and step-by-step problem-solving.
    1. Use our online water assistant to diagnose your water quality issues.
    2. This article covers more situations if the app didn't help solve your problem.
  2. I need to solve an underlying contamination issue in my hot tub; maybe it's biofilm?
  3. How to avoid future problems and keep your hot tub clean?
  4. What kind of sanitizers can I choose from?
  5. What is the best way to maintain my hot tub water?
  6. How to test the water in my hot tub?

FAQs on How to Refill Your Hot Tub

How often should you refill hot tub? How often should you empty and clean a hot tub?

Emptying and cleaning your hot tub every 3-4 months is typically recommended. However, this can vary depending on how often you use it, the quality of your water, and other factors.

What do I add when I refill my hot tub?

When you refill your hot tub, you'll need to add water, a sanitizer, and often other chemicals to maintain pH and alkalinity levels.

Can you refill hot tub with a garden hose?

Yes, you can refill your hot tub with a garden hose. However, you'll need to make sure the water is clean and free of contaminants. You may also need to add a filter to the hose if your water is particularly dirty.

How long does it take to heat a hot tub after filling?

Heat your hot tub after filling it can take anywhere from a few hours to a day or more. The exact amount of time will depend on your hot tub's size, the water's temperature, and other factors.

Can I heat my hot tub while filling it?

No, you should not heat your hot tub while filling it. Doing so can damage the pump and other components.

Can you drain and refill a hot tub in winter?

Yes, you can drain and refill a hot tub in winter. However, you'll need to take steps to protect the components from freezing. You may also consider using an outdoor hot tub heater to warm the water.

How do I top up my hot tub water in the winter?

If you need to top up your hot tub water in the winter, you can do so by adding a garden hose or other source of clean water. You'll need to take steps to prevent the components from freezing, such as adding a heater.

Do you have to empty a hot tub after every use?

No, you do not have to empty a hot tub after every use. However, you may need to drain and refill it more often if you use it frequently or if the water quality is poor.

Can I leave my hot tub empty for a week?

If necessary, you can leave your hot tub empty for a week or more. However, you'll need to take steps to protect the components from freezing and damage. You may also consider using an outdoor hot tub cover to keep the elements out.

Wrapping Up Refilling Hot Tubs

Now that you know all about refilling hot tubs, it's time to start! If you're still unsure what to do or which steps to take, download the O-Care app for weekly maintenance and step-by-step problem-solving.

Draining and refilling your hot tub is essential for maintenance, but it's also important to take a few extra steps afterward to ensure everything is running smoothly.

Following the tips in our video will help ensure that you have a pleasant and relaxing experience each time you step into your hot tub.