The presence of high cyanuric acid in your hot tub can lead to poor sanitization. Chlorine cannot sanitize your hot tub’s water if the cyanuric acid is high. Thus, it is important to put it to the correct level.
The most effective way to reduce the cyanuric acid in your hot tub is to drain and refill it with new water partially. Alternatively, you can use cyanuric acid reducers that you can purchase from Spa stores. Rainwater may also help reduce your hot tub’s cyanuric acid level, but it may also affect its alkalinity level.
Although cyanuric acid is not extremely dangerous, it is regulated in most states. It means that it has some negative effects on human health in one way or another. Stick around to learn more details on how to lower the cyanuric acid in your hot tub.
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What Causes Cyanuric Acid to be High in a Hot Tub?
Before discussing why the cyanuric acid level in your hot tub increases, I will first give you a brief overview of what it is.
Cyanuric acid is a pool-balancing product that helps prolong the life of chlorine. Chlorine can easily deteriorate when exposed to ultraviolet. With the help of cyanuric acid or chlorine stabilizer, chlorine can properly sanitize your hot tub.
Related Read: What is a Stabilizer in a Hot Tub?
Cyanuric acid is a critical chemical in maintaining your hot tub. It helps keep your hot tub clean and sanitized.
A hot tub’s ideal cyanuric acid level is between 30 and 50 parts per million (ppm). Hot tub owners always face the issue of lowering the cyanuric acid level in their hot tubs because it does increase over time.
The big question is, what causes the cyanuric level to increase? Does it happen naturally?
Stabilized chlorine tablets are the common culprit of high cyanuric acid in a hot tub. The chlorine tablets you use to sanitize your hot tub include dichlor and trichlor. These chemicals are over 50% cyanuric acid.
The more chlorine tablets you apply, the higher the cyanuric acid in your hot tub. There is no way that the cyanuric acid level will decrease without you taking action because it does not evaporate.
This chemical stays in the water, so it will continue to increase over time. The best way to deal with the increasing cyanuric acid in your hot tub is to release a portion of its water.
If adding chlorine tablets to the hot tub increases the cyanuric acid content, is it okay not to apply it? It may not be the best idea. It is a must because you need to sanitize your hot tub.
However, you can control the chlorine tablets you add. As a best practice, you can do a partial drain and refill once a month to keep the cyanuric acid level at the acceptable range.
How Does High Cyanuric Acid Affect the Hot Tub?
A high cyanuric acid level in your hot tub can have multiple effects. Too much of it will make chlorine less effective as a sanitizing agent. It can make your water cloudy, algae may start to grow, and the water may start to smell.
Excessive cyanuric acid in your hot tub also distorts alkalinity readings. Because of this, you might find it difficult to put your hot tub at a proper alkalinity level. Additionally, it can drop the pH level of your hot tub.
When the pH level is low, you are prone to skin irritations. It makes your hot tub not very safe for soaking.
Is it Safe to Use a Hot Tub With High Cyanuric Acid?
It is not that dangerous if we only talk about the direct effect of high cyanuric acid levels on human health. However, it is categorized as a hazardous substance. Thus, too much exposure to it may adversely affect human health.
Experts say that soaking in water that is over 150 ppm may cause skin and eye irritations. The World Health Organization (WHO) determined the maximum tolerable level of cyanuric acid to be 100 ppm. You might find this fact sheet about cyanuric acid helpful.
To answer the question if it is safe to use a hot tub with a high cyanuric acid level, I would say NO, it is not very safe. Aside from the possible irritation, you would likely pick up bacteria that can cause infections.
High cyanuric acid will prevent your sanitizing agent from doing its job properly. If your hot tub is poorly sanitized, bacteria can exist in the water and cause problems.
One indication that your hot tub has high cyanuric acid is smelly water. Smelly water indicates the presence of bacteria. I am sure that most people don’t like soaking in a smelly hot tub.
Ways to Bring the Cyanuric Acid Level Down in a Hot Tub
Partial Drain
Hot tub experts agree that diluting the water is the most effective way to reduce the cyanuric acid level of your hot tub. This method is done by partially draining your hot tub water and refilling it with a fresh one.
You are removing the excess cyanuric acid by draining a portion of your water. When reducing the cyanuric acid in your hot tub, ensure it doesn’t go below 30 ppm.
If the cyanuric acid goes very low, your chlorine loses protection from the sun’s ultraviolet rays. When this happens, the chlorine can easily decompose.
Although the draining process sounds simple, you must consider a few things. Please check the quick steps to take below:
Step 1: Measure the cyanuric acid level of the hot tub using test strips before you start draining. Doing this will give you an idea of how much you need to lower. Remember to keep the cyanuric acid level at the correct level of 30 to 50 ppm.
Step 2: Partially drain the tub using a submersible pump or a hose. Do not drain the water too low, as you might have a low cyanuric acid level. You must only drain the hot tub according to the excess cyanuric acid level (if the cyanuric acid level is 15% higher, only drain 15% of the water).
Step 3: When the tub is half empty, refill it with fresh water. Ensure that the refill hose points down the center of the standpipe to reduce airlocks. Also, ensure that you are not using hot water to refill the tub.
Step: 4: Test the cyanuric acid level again. You can drain more if it is still high or until it reaches the correct level.
Cyanuric Acid Reducers
If you do not like draining your hot tub, you can use cyanuric acid reducers that you can buy in the market. However, this might not be the most economical option. Cyanuric acid reducers can be very expensive.
The result of using reducers is also not guaranteed. Some hot tub and pool owners who tried using cyanuric acid reducers report that it did not work.
The main plausible reason those who have used cyanuric acid reducers report that it did not work could be the algaecides, clarifiers, or phosphate content of the hot tub. Most hot tub owners apply these chemicals.
There are also a few things to consider when using cyanuric acid reducers:
- It does not work in the presence of clarifiers, algaecides, or phosphate (you must consider this before buying one).
- Your hot tub water temperature should be at least 65 degrees Fahrenheit.
- You need to ensure that your hot tub’s pH and alkalinity levels are at the correct level before adding the reducer (it means you would need to measure the alkalinity and pH level before applying the product).
Therefore, before considering this option, you must also recall if you applied these chemicals. Otherwise, it will be a complete waste of resources.
If you wonder what a cyanuric acid reducer is, you can check the Bio-Active BA-CAR-08 100-Percent Cyanuric Acid Reducer Powder on Amazon.
Will Rainwater Lower Cyanuric Acid?
Rainwater is another alternative to reduce the cyanuric acid level of your hot tub. This option is easy if you have an outdoor hot tub because you can remove the cover and wait for the rain.
If it rains heavily, you might need to put the cover back not to drop the cyanuric acid level very low. Otherwise, you will have to face another problem.
The question is: Is this the best option? Although it effectively reduces the cyanuric acid level, it may not be the best option.
Rainwater is naturally acidic, which may destroy your hot tub’s water chemistry. Rainwater can potentially affect your tub’s alkalinity and pH level.
After reducing your cyanuric acid level, I suppose you do not want to face another problem with your hot tub’s alkalinity and pH level. In that case, it is best to dilute your hot tub by partially draining its water.
Conclusion
Cyanuric acid level reduction is important to ensure optimal sanitization of your hot tub. A high cyanuric acid level in your hot tub can affect the chlorine’s ability to sanitize the water.
You should keep the cyanuric acid level of your hot tub at 30 to 50 ppm. The most effective way to lower the cyanuric acid level in your hot tub is to drain the water and replace it with fresh water partially. You can also consider using cyanuric acid reducers, which can be expensive.
