How to Raise Chlorine Levels in a Hot Tub?

While testing the water in your hot tub, it’s very common to discover that the chlorine levels are low. So you may be wondering, how do you raise chlorine levels in a hot tub? Here is the answer to that.

To raise the chlorine levels in a hot tub, you need to oxidize or shock the hot tub with chlorine shock. This means you need to add more chlorine to the water. Hot tub chlorine shock will destroy chloramines in the water and raise the chlorine level.

But that’s not all. There is more to know about raising the chlorine levels in your hot tub and this post digs right into the topic.

Let’s dive in.

What Happens If Chlorine Is Too Low In A Hot Tub?

When the chlorine level in your hot tub is too low, the hot tub will become prone to bacteria attacks and algae bloom. The hot tub water will also become murky and will begin to smell because there isn’t enough chlorine sanitizer in the water to destroy the contaminants in the water.

When the chlorine level is low, the hot tub becomes defenseless. This means microorganisms like bacteria can multiply faster in the water. These microorganisms need a warm and moist environment to grow. Your hot tub already provides warmth and moisture which means ordinarily, your hot tub is a potential home to these microorganisms.

So if the chlorine which is meant to prevent the growth of these microorganisms falls below the needed range, the hot tub will become affected by bacteria, fungi, mold, and even algae.

The hot tub water will also become smelly (hot tub chlorine smell). When the chlorine level is low, hot tub scum will also be present in the water. Hot tub scum is formed from the accumulation of dirt, grime, body oils, sweat, food residue, and the likes. The presence of scum in the water will cause it to start to smell.

Low chlorine levels will also cause cloudy and murky hot tub water. The combination of algae, bacteria, mold, and hot tub scum in the water will make the water get cloudy and murky when it gets heated. If this continues, you will have green water.

Low chlorine levels in the hot tub also mean the water alkalinity will increase. When this happens, you will notice a hot tub scale forming on the metal parts of the hot tub.

Also, soaking in hot tub water with low chlorine levels is unsafe. It can cause water-borne diseases and health infections to the bathers.

As you can see, low chlorine levels in your hot tub can cause tons of damages. So how do you raise the chlorine levels in a hot tub? Let’s find out.

Related Read: How To Lower Chlorine Levels in a Hot Tub?

How To Raise Chlorine Levels In A Hot Tub?

Here is how to raise the chlorine level in your hot tub. From this method, you will find out the best way to raise the chlorine level of your hot tub by using chlorine shock.

1. Find Out Why You Have A Low Chlorine Level

Find Out Why You Have A Low Chlorine Level

The first step is to inspect the hot tub to know why you are having a low chlorine level. If the reason is because of too many contaminants in the water, then you might just need to drain and clean the hot tub.

If the reason is a lack of shade or hot tub cover, then you know you need to buy and or start using the hot tub’s cover more frequently.

When you know what is causing a low chlorine level, you will know how to prevent it after you have increased it.

2. Test the water

Test the water

Of all hot tub chemicals, hot tub chlorine shock is the most acidic. You don’t want it in your eyes, in your lungs, or on your skin. So, make sure to protect yourself.

The next step is to test the level of chlorine in the water. For this, you will need your hot tub test strip. The amount of chlorine in the water will let you know how much shock you need to add to raise it.

You should also ensure to test the water pH level. The pH level has to be between 7.4 and 7.8 on the pH scale before you can add chlorine shock.

3. Turn On the Hot Tub And The Jets

Turn On the Hot Tub And The Jets

The next step is to turn on the hot tub and the jets. It’s important to ensure that the hot tub is on and running while you attempt to raise the chlorine level. This is because you will most likely add a substance to raise the chlorine level.

The substance will either be in granular, liquid, or tablet form. The water has to be in circulation so the substance can dissolve and mix in the water easily.

When the jets are on, you can also turn on the circulation pump to keep the water running through the hot tub plumbing.

4. Shock The Water

Shock The Water

Remember for this method, we are using chlorine shock to raise chlorine in the water. You can also use non-chlorine shock but this wouldn’t work anywhere as well as chlorine shock.

You should ensure the jets are running while you add the chlorine shock into the water. The chlorine shock would have a few instructions indicated on the container of the shock chemical.

Ensure to follow the instructions on the container regarding how to add the content to the water. If you add a lower amount than is needed, the chlorine wouldn’t rise to the needed level. If you add too much shock, the water will become acidic.

5. Leave The Hot Tub Open

Leave The Hot Tub Open

You should leave the hot tub uncovered for at least 15 minutes immediately after shocking. This would allow the shock to fully oxidize the water. The hot tub chlorine shock will break up the used up chlorine to release more free chlorine into the water.

The shock will also add to the level of chlorine in the water and kill the contaminants in it. After 15 minutes, you can cover the hot tub and leave it for a while.

6. Re-test The Water

Re-test The Water

The next step is to retest the chlorine levels of the water. If you added the right amount, the free or active chlorine level in the water would be between 2 and 4 ppm. There would be no combined chlorine in the water and the total chlorine will be the same as the free chlorine.

If any of your hot tub chlorine levels are not within this range after adding the chlorine shock, then that means you didn’t add the right amount. You added maybe too much or too little.

When the free chlorine level is below 5 ppm, the tub is safe to use again. This also means you have successfully raised the chlorine level of your hot tub.

Related Read: Can You Use a Hot Tub With High Chlorine?

What Should The Chlorine Levels in My Hot Tub be?

The free chlorine level in your hot tub should be between 1 and 3 ppm (parts per million). The combined chlorine level should be 0 ppm while the total chlorine level should be between 2 and 4 ppm. Any chlorine reading below or above this range is not ideal for a hot tub and can be dangerous to soak in.

When it comes to measuring chlorine levels in a hot tub, there is usually confusion about which type of chlorine to test for. On your hot tub test strip, there is usually a provision to test for free chlorine, combined chlorine, and total chlorine. So which one of these tells you the chlorine levels in your hot tub?

Well, they all tell you how much chlorine is in the hot tub but the most important is the level of free chlorine in the hot tub water.

The level of free chlorine should be between 1 and 3 ppm. Free chlorine measures the chlorine that can still battle contaminants in the water. It tells you the level of active chlorine in the water.

Combined chlorine or chloramines on the other hand tells you how much chlorine has been used up in the water. The level of combined chlorine in a well sanitized hot tub should be 0 ppm. If the level of combined chlorine rises above 0.5 ppm, it means that there are too many contaminants in the water.

The addition of the free and combined chlorine is what is known as total chlorine. If the free chlorine ever falls below 1ppm, it means that the chlorine level in the water is low and needs to be raised.

But what causes the chlorine level to be low? Let’s take a closer look.

Why Are My Chlorine Levels Low?

The chlorine level in your hot tub is low because there are too many contaminants in the water. When the level of contaminants in the water is high, the chlorine in the water will get used up very quickly and this will result in a low chlorine level.

There are several other causes for a low chlorine level in the hot tub such as high water temperature and clogged filters. But usually, the culprit for a low chlorine level is a high level of contaminants in the water.

Let’s check out some other causes of a low chlorine level in your hot tub.

High Water Temperature

If the water temperature in your hot tub is constantly kept above 100 degrees Fahrenheit even when the hot tub is not in use, it can cause a low chlorine level.

The hotter the water in the hot tub is, the faster the rate of chlorine loss through evaporation.

When you add chlorine to the hot tub, the chlorine gets mixed with the water because chlorine dissolves in water quickly. So when the water is being heated, the chlorine that has dissolved in the water is also heated with the water.

If you keep the water temperature above 100 degrees for a long time, the rate of chlorine loss through evaporation will be high too. This can be the reason you are having a low chlorine level in your hot tub.

No Shade Or Hot Tub Cover

If the hot tub is left without a shade or a hot tub cover, the chlorine level will drop quickly. The sun’s UV rays are not beneficial to the hot tub. This is because the UV rays burn the chlorine in the water and cause a depletion quickly.

So if the hot tub is left uncovered and unprotected from the rays of the sun, the chlorine levels will drop very quickly.

Unbalanced Water Chemistry

To keep the chlorine level in your hot tub at the right range, the water chemistry needs to be balanced. The total alkalinity and pH levels especially have to be within the right range.

If the total alkalinity goes above 120 ppm, then the pH levels of the water will go wonky and this can cause the chlorine levels to drop.

This is because chlorine works best in low pH levels so if the total alkalinity and pH levels are unbalanced, the chlorine sanitizer wouldn’t work as it should and this will lower the chlorine level in the water.

Related Read: Can You Shock a Chlorine Hot Tub With Bromine?

Dirty Filters

The filters in your hot tub keep the water clean by trapping dirt and debris that get introduced into the water.

If the filters get clogged up by dirt, they wouldn’t be able to trap any debris in the water. This means the responsibility now falls on the chlorine in the water to break down and destroy these contaminants.

This will result in more chlorine use in the water especially if the contaminants being destroyed are not organic. More chlorine use means quick chlorine depletion and subsequently, low chlorine levels.

Other possible causes for a low chlorine level in the hot tub include biofilm in the plumbing lines and inadequate chlorine sanitizer in the water.

Can Low Chlorine Levels Damage Your Hot Tub?

Low chlorine levels in a hot tub can damage the hot tub. Hot tub water with low chlorine will have high alkalinity. When this happens, the metal parts of the hot tub will start to develop a hot tub scale.

When the hot tub has a low chlorine level, the hot tub components can become damaged. Low chlorine levels will cause staining on the shell of the hot tub. This is because the hot tub will have several contaminants that will cause the water to either have a brown or green tint. The brown or green water will start to stain and discolor the inner walls of the hot tub.

The hot tub circulation pump can also get damaged as a result of clogged pipes. Low chlorine levels result in high alkalinity. High alkalinity will lead to a hot tub scale that can clog the plumbing lines of the hot tub over time.

Hot tub scale from high alkalinity can also cause a blown-out heater. If the scale covers the heating mechanism, the heater wouldn’t get enough water and can blow out.

The jets and hot tub filters are also not safe if there are low chlorine levels in the water. The filters will become clogged by scum and debris. The jet holes can also become blocked by biofilm and hot tub scum.

Final Words

Overall, having low chlorine levels in your hot tub should be heavily avoided. This is because a low chlorine level can cause hundreds of dollars in damages to the hot tub before you even notice it, especially if you rarely use the hot tub.

So to avoid this, ensure the chlorine levels in your hot tub are always kept in check. You should also shock the hot tub once a week to get rid of combined chlorine or chloramines.

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