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Ways To Increase Free Chlorine In Hot Tub


If you just got your hot tub, one way to properly maintain it is to figure out how to increase free chlorine in hot tub. Maintenance procedures in keeping water balance chemistry must be executed like keeping the chlorine level in check all the time. Once the level of chlorine is lower than the recommended, action to raise it must be done to avoid unhealthy hot tub water which is a disturbance to users.

In this article, we are going to get to know free chlorine better, identify causes why chlorine is getting low, and ways that we can raise it to the recommended level making sure that bacteria, germs, and other contaminants are killed.

Part 1. What Is Free Chlorine?

To easily understand how to increase free chlorine in hot tub, free chlorine must be understood well. The amount of chlorine that you can say is available to sanitize your hot tub is called free chlorine. It is the chlorine that has not been used up and is still present in your hot tub water to kill bacteria, germs, and other organic contaminants. Once free chlorine is not enough, harmful microorganisms are highly possible to build up. To keep it effective, the level must be maintained in the range between 3 and 5 ppm.

Test Strips

It is one of the types of chlorine that are present in your hot tub water. Free chlorine is the available chlorine that is active and can be used to kill algae and get rid of the present contaminants in the hot tub water.

There is also combined chlorine in hot tubs, which is also called chloramines is the type of chlorine in hot tubs that are already used up. In hot tubs, it must be made sure that the combined chlorine level should be below 0.5 ppm. Once combined chlorine is too high, chlorine in hot tubs will stop working effectively, and you will begin to sense the smell of chlorine in the air.

Once free chlorine and combined chlorine are added, total chlorine is obtained. Once the level of total chlorine is the same as the free chlorine level or is 3 ppm, this will mean that all the chlorine present in the hot tub is still free chlorine, and can still be utilized to clean the hot tub and work as a sanitizer.

Type Recommended Amount
Free Chlorine 3 ppm (ideal)
Combined Chlorine 3 ppm (ideal)
Total Chlorine < 3.5 ppm

Part 2. Why is Free Chlorine Low in the Hot Tub?

The main reason why it is needed to figure out how to increase free chlorine in hot tub is because it is low. What causes your free chlorine to get low?

1. Presence of contaminants.

One of the possible reasons why free chlorine in hot tubs is low is because of the presence of contaminants. Once it has become too low, it is being used up to remove contaminants in hot tubs. Once there are lots of leaves, branches, twigs, and other organic contaminants, or inorganic contaminants like hair, soap, and lotion products are present in the hot tub, free chlorine can be low. To prevent your free chlorine from being low because of these contaminants, you have to do complete vacuuming, brushing, and skimming to remove buildup and debris. Make sure that the chlorine level is maintained, and shocking the tub would also help.

2. There are higher bather loads.

Once your hot tub is being used all the time, it means higher battery loads. The more people who use the hot tub, the greater the possible amount of contaminant is. Once there are many contaminants to remove, free chlorine is used to kill all of them. Always make sure to execute a good shock after a hot tub pool water dipping.

3. Water chemistry is not proper.

As a hot tub owner, it must be understood that all the chemicals that are present in your tub are connected and affect each one. Once these chemicals are not balanced, sanitizer in the tub won’t work well, and the chance of algae and bacteria growing is higher. Once there are many algae and bacteria, free chlorine will be consumed. It is a must to watch chemical levels and make sure each one complements the other by balancing each of them based on the required level.

4. The UV rays from sunlight.

It must be understood that the sun causes chlorine ions to burst and separate, causing destruction. If you have an uncovered hot tub, UV rays of the sun will cause free chlorine levels to lower by 2 to 4 ppm daily. So, as an owner of outdoor tubs, you have to buy covers that can protect your water from the UV rays of the sun.

These are only some of the major reasons why there is low free chlorine in your hot tubs, the more reasons why it is a must to figure out how to increase free chlorine in hot tub.

Part 3. How to Increase Free Chlorine in Hot Tub?

Now, that we are finally aware of the real causes why free chlorine in hot tubs is low, we must hurry and figure out how to increase free chlorine in hot tub. To give a guide to many hot tub owners out there, we have enumerated some of the things that can be tried and executed.

  1. Once the chlorine or bromine level in your hot tub reaches a level that is below 2 ppm, do shock.
  2. Try to increase the level of chlorine or bromine that you are using.
  3. Water balance is really important to keep your free chlorine level in control. It is also critical and essential when it comes to proper hot tub sanitization. Once the pH level is off, chlorine can be ineffective.
  4. There might also be algae present in your hot tub, and bromine or chlorine will likely be consumed faster because of this. To get rid of algae, it is recommended that you shock your tub, or you can also try to add an algaecide. Brushing the side parts of the spa might also prevent free chlorine from being quickly consumed.
  5. You can also check the settings of your dial. It must be done if you are using salt chlorine generators. You can adjust the setting of the dial one setting per day until you have finally reached the correct setting to maintain the needed amount of bromine or chlorine. Once you have noticed that there are abnormal conditions such as heavy rain, you can start shocking the water to maintain a free chlorine level.
  6. You can also try to drain and refill the hot tub, especially if it has been three months already since you last drained and refilled it. After draining the water, be sure to clean the surface of the spa as well as filter cartridges, and refill it once more with fresh water.

Once you have made sure that you have done any of the ways discussed above, and yet the free chlorine level is still low, you can resort to shocking. It may be because of the large number of contaminants present in your hot tub, and free chlorine may not be available enough to battle it. Here is an article to learn more about the Maintenance of Hot Tub.

Part 4. FAQs

1. Is it Safe to Go in a Hot Tub with Low Chlorine?

Anyone should not use the hot tub if the level of chlorine is not stable. It is important to remember since it can pose effects on the human body and skin. The total chlorine level must be in the range between 2 and 4 ppm. So, it must be a routine that after you have finished a swim spa, start treating your hot tub water to maintain the chlorine and pH levels.

2. How Much Shock Does It Take to Increase Free Chlorine?

To properly treat or shock your tub, conditions that caused its free chlorine to lower that much must be considered. This will determine how much shock must be used. In case the water is looking good, and you just want to have a boost of chlorine a little, you can start adding 1 ounce of PoolClever concentrated chlorine granule for 500 gallons of water.

3. How Often Should I Test the Free Chlorine Level in My Hot Tub?

It is important to figure out the frequency of a test for free chlorine must be done in your hot tub. The standard is to conduct test-free chlorine concentration as well as pH testing two times a day. You can also do it more often in case you use your hot tubs or pool more often.

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