Cyanuric Acid is Your Enemy: The Hidden Threat of Using Chlorine Tablets in Your Swimming Pool.

As a DIY homeowner dedicated to maintaining a crystal-clear swimming pool, you’re likely well-versed in the usual suspects of pool care: Ph levels, chlorine, and perhaps even calcium hardness. But lurking beneath the surface, an often-misunderstood chemical could be undermining all your hard work: Cyanuric Acid AKA (Stabilizer).

Understanding where Cyanuric Acid comes from and how to manage it isn’t just pool care 101 – it’s your first line of defense in keeping your swimming pool safe and enjoyable.

What is Cyanuric Acid? Cyanuric acid (CYA), commonly known as pool stabilizer or conditioner, is an essential chemical in the toolkit of swimming pool maintenance. Its primary role is to stabilize chlorine, protecting it from the sun’s ultraviolet (UV) rays. Without CYA, the chlorine in your pool would degrade rapidly, rendering it ineffective as a sanitizer and forcing you to add chlorine more frequently. In this sense, cyanuric acid acts like sunscreen for your pool’s chlorine, ensuring that it continues to combat algae and bacteria without being neutralized by sunlight.

The Benefits of Cyanuric Acid in Swimming Pools: CYA is helpful for several reasons:

1. Chlorine Stabilization: By forming a weak bond with chlorine, it helps maintain an active level of sanitizer in the pool for a longer time.

2. Cost Efficiency: It reduces the frequency with which you need to add chlorine, saving you both time and money.

3. Reduced Maintenance: With stabilized chlorine, your pool water stays balanced longer, which means less frequent maintenance.

The Dark Side of Cyanuric Acid: When Too Much Cyanuric Acid Becomes Harmful

While CYA can be a swimming pool’s best friend, it can quickly turn into its worst enemy if levels get too high. High cyanuric acid levels can lead to a condition known as chlorine disruption, where the stabilizer binds too tightly with the chlorine, slowing it down and making it less effective as a disinfectant. This can create a false sense of security, as standard chlorine tests might show adequate chlorine levels like the recommended levels of 2-4ppm, while the active, free chlorine – the type that kills germs—is actually far too low and ineffective.

Here’s why high CYA levels are harmful:

1. Ineffective Sanitization: At high levels, CYA slows down chlorines ability to kill bacteria reducing the effectiveness of chlorine thus increasing the risk of algae and bacterial growth.

2. Altered Chemistry: An elevated CYA level can skew your pool’s chemistry, making it harder to maintain the pH and alkalinity balance. Now your water test becomes a math problem. Learn more about the math of pool care in future articles.

3. Cloudy Water: High CYA levels often result in cloudy pool water, which is both unsightly and a sign of poor water quality. This happens because high cyanuric acid levels render chlorine helpless and lethargic in its battle to kill bacteria and keep pool water safe to swim.

4. Health Risks: When chlorine is not effectively sanitizing the pool, swimmers are at a higher risk of contracting illnesses from bacteria and viruses present in the water. High cyanuric acid levels require a higher chlorine level in order to maintain a safe swimming environment. High chlorine levels can be harmful and cause respiratory issues, skin and eye irritations, hair and swim suit damage and fading.

5. TDS Increase: High levels of CYA contribute to the total dissolved solids (TDS) in your pool, which can further complicate water balance and require a partial or complete water replacement.

Managing Cyanuric Acid Levels: Strike the Right Balance

To prevent the downsides of high CYA levels, it’s crucial to regularly test your pool water and keep cyanuric acid levels within the recommended range, typically between 30 and 50 ppm (parts per million). Here are some tips for managing CYA…

1. Regular Water Testing: Use a reliable test kit to check CYA levels at least once a month or more frequently if you’re using cyanuric acid-based chlorine products.

2. Smart Chlorination: Consider using non-stabilized chlorine like liquid chlorine if your CYA levels are consistently high and stop all use of chlorine tablets during the time it takes to reduce your cyanuric acid level.

3. Dilution: If CYA levels exceed the recommended range, partially drain and refill your pool with fresh water to dilute the concentration. A good dose of fresh water helps in so many ways.

4. Non-stabilized Shocks: When shocking your pool, use non-stabilized chlorine shock to avoid increasing CYA levels. For example, do not use Sodium Dichlor granular chlorine along with TriChlor Chlorine Tabs. Both of these products contain Stabilizer. Using these two products together will cause your Cya to skyrocket. I recommend using liquid chlorine above all types of chlorine available. Liquid chlorine does not contain stabilizer and works well with chlorine tablets.

5. Learn how Chlorine Tabs are used: Chlorine Tabs are meant to be used during the months of May – September and at a rate of one 3″ Tablet per 10,000 Gallons per week along with the required amount of liquid chlorine to chlorinate your pool. Do not stack your chlorinator full of 3″ tablets and think you’re doing your pool any good.

In conclusion, while cyanuric acid plays a vital role in swimming pool care, it can quickly become your enemy if not managed properly. By staying vigilant with testing and adjusting your pool’s CYA levels, you’ll ensure a safe, sparkling pool that’s free from the hidden threats of high cyanuric acid. Remember, in the world of pool care, knowledge is power—and knowing how to handle cyanuric acid is the key to unlocking a summer of uninterrupted pool time.

Would you like to know what your real water test numbers are and what to do to adjust them?  I highly recommend using a Taylor Technologies Test Kit. I’ve tested with Taylor for over 40 years and use it daily in my pool care business. 

If you have high cyanuric acid, comment below. I will send you a free table you can use to determine how much chlorine is needed based on your current cyanuric acid level.

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