How to Lower Cyanuric Acid (CYA) Levels in Your Pool – AQUASTRONG Guide

Cyanuric acid (CYA), often called pool stabilizer or conditioner, is a crucial chemical in maintaining your pool’s water balance. It protects your chlorine from being broken down by the sun’s UV rays, helping to keep your pool clean and safe. However, while cyanuric acid plays a key role in pool care, too much of it can cause problems. High CYA levels can make chlorine less effective, leading to unsanitary water and potential damage to your pool’s surfaces.

In this guide, we’ll explain why high CYA levels can be harmful, how to lower cyanuric acid in your pool, and the best practices to maintain a healthy balance of pool chemicals.

What Causes High Cyanuric Acid Levels?

The most common cause of elevated CYA levels is the use of stabilized chlorine products, such as dichlor or trichlor. These chlorine sources contain CYA to protect the chlorine from UV degradation, but over time, the cyanuric acid can accumulate in your pool water.

When stabilized chlorine is added regularly, the CYA levels gradually increase. Unlike chlorine, which dissipates over time, cyanuric acid remains in the water as it evaporates, causing a gradual buildup. If you’re using stabilized chlorine products and your pool is exposed to constant sun, it’s easy for CYA levels to rise beyond the recommended range.

Ideal Cyanuric Acid Levels

To maintain proper water chemistry, it’s important to keep CYA levels between 30–50 parts per million (ppm). In saltwater pools, levels may be slightly higher, but anything above 50 ppm can begin to affect the effectiveness of chlorine. When CYA levels rise above 100 ppm, the chlorine in your pool may become ineffective, leading to cloudy water, algae growth, and poor sanitation.

Why Should You Lower High Cyanuric Acid Levels?

Excessive cyanuric acid in your pool can cause several issues:

1. Reduced Chlorine Effectiveness: High CYA levels bind to chlorine, reducing its availability to kill bacteria, algae, and other contaminants. This can lead to unsanitary water, making your pool more susceptible to algae blooms and bacterial growth.

2. False Water Chemistry Readings: Elevated CYA levels can skew your pool’s other chemical readings, especially when it comes to chlorine levels. You may struggle to maintain the proper balance of your pool chemicals, leading to imbalanced water.

3. Damage to Pool Surfaces: High CYA concentrations can result in lower pH levels, which can harm your pool’s plaster surfaces, causing them to deteriorate over time.

How to Lower Cyanuric Acid Levels in Your Pool

If you find that your CYA levels are too high, don’t worry—there are several ways to lower them. The most effective method is to dilute your pool water by draining and refilling your pool. Here's how to do it:

1. Drain and Refill Your Pool

The most reliable way to reduce cyanuric acid is by partially draining your pool and refilling it with fresh water. This dilutes the cyanuric acid concentration in your pool.

Steps to Lower CYA by Draining:

• Test Your Water: Before draining, test your pool water with test strips or a liquid test kit to determine the current CYA levels.
• Drain Some Water: Using a submersible pump, a siphon, or the "waste" setting on your filtration system, drain a portion of the water. Be careful not to let the water level drop below the skimmer to avoid damaging the pump.
• Refill Your Pool: Refill your pool with fresh water, and test the CYA levels again.
• Repeat if Necessary: If CYA levels are still too high, repeat the process until they fall within the ideal range of 30–50 ppm.

2. Use a Cyanuric Acid Reducer

There are chemical products available that can help reduce cyanuric acid levels in your pool. These products are designed to break down cyanuric acid, but they are generally less effective than draining and refilling your pool. Cyanuric acid reducers are also expensive and may not work well if your levels are extremely high.

Considerations:

• Cyanuric acid reducers are more effective in pools with moderate CYA levels. If your CYA is significantly elevated, draining and refilling is likely your best option.
• Follow manufacturer instructions closely when using any chemical reducer.

3. Reverse Osmosis Filtration

If you have persistently high CYA levels, you might want to consider using a reverse osmosis (RO) filtration system. This method involves passing pool water through a fine membrane to remove contaminants, including cyanuric acid.

Advantages:

• Reverse osmosis filtration can reduce not only cyanuric acid but also calcium hardness and total dissolved solids.
• This method is particularly useful in areas with water restrictions, as it conserves more water than a full drain-and-refill approach.

Drawbacks:

• Reverse osmosis systems are costly to install and operate.
• The filtration process generates wastewater, which could be a concern in regions with water conservation policies.

Preventing High Cyanuric Acid Levels in the Future

Once you’ve successfully lowered your CYA levels, it’s important to maintain them to avoid future issues. Here are a few tips:

1. Limit the Use of Stabilized Chlorine: Opt for unstabilized chlorine products (like calcium hypochlorite or liquid chlorine) that don’t contribute to CYA buildup. If you must use stabilized chlorine, consider switching to alternatives with lower CYA content.

2. Monitor CYA Regularly: Test your pool water frequently to ensure your CYA levels remain within the optimal range. This is especially important if you use stabilized chlorine products.

3. Use Pool Covers: If your pool is exposed to constant sunlight, consider using a pool cover during non-swim seasons. This can help reduce the effects of UV rays on your chlorine and prevent rapid CYA accumulation.

Frequently Asked Questions About Cyanuric Acid Levels

How do I know if my CYA levels are too high? Test your pool water using test strips or a liquid test kit. CYA levels over 50 ppm are considered high and can reduce chlorine effectiveness.

Can I swim in a pool with high cyanuric acid? While it’s generally safe to swim in a pool with high CYA levels, the water may not be properly sanitized. Elevated CYA can reduce chlorine’s effectiveness, leading to unsanitary water.

How can I prevent high CYA levels in the future? Limit the use of stabilized chlorine products and regularly test your water to maintain proper chemical balance. Consider using unstabilized chlorine for routine sanitation.