How To Lower Cyanuric Acid In A Pool

Owning a pool is the dream of so many people. Lazing in your own backyard pool on a hot summer’s day sounds idyllic. However, owning a pool means maintaining it properly, especially if it is outdoors. 

Cyanuric acid, also known as CYA, pool stabilizer, and pool conditioner, is a chemical that is used to improve the effectiveness and longevity of chlorine in outdoor swimming pools.

How to Lower Cyanuric Acid in a Pool

This acid goes to work like a sunblock for the chlorine, protecting it from becoming diluted. Over time, this keeps your pool cleaner for longer.

While cyanuric acid is important for the upkeep of the water, the levels need to be carefully monitored.

The most ideal ranges for cyanuric acid in a pool are between 30 and 50 parts per million (ppm). If the levels of cyanuric acid go above 80 ppm, it will no longer be beneficial to your pool.

The chemistry of the pool will be off-balance and the chlorine will become unstabilized. The good news is that you can restore your pool’s chemistry with a cyanuric acid reducer.

Read on to find out how to lower cyanuric acid levels in your pool and discover why this occurs and why you should tackle it as soon as possible. 

Why does your pool have high levels of Cyanuric acid? 

Every pool requires chlorine to keep the water clean. Whether the chlorine contains cyanuric acid can depend on the type of chlorine you use. In general, stabilized chlorine contains CYA while unstabilized chlorine does not.

In the majority of cases, the reason for high CYA levels in a pool is too much stabilized chlorine. When the pool begins to evaporate, CYA remains in the water such as other chemicals like calcium and salt.

For instance, 1 pound of trichlor in a 10,000-gallon pool could raise the CYA levels by up to 6 ppm. Remember, the ideal range of CYA in a pool is around 30 ppm to 50 ppm. Therefore, it is plain to see how easy levels can rise.

High cyanuric acid effects 

Several issues can arise if your pool has high levels of cyanuric acid. Here are some of the main problems that your pool could face:

Stops chlorine’s effectiveness 

Your pool’s chlorine can become a lot weaker if the levels of CYA are too high. Therefore, your pool’s water will become dirtier as chlorine can’t do its job effectively.

This is sometimes referred to as “chlorine lock” where the high levels of CYA overpower the free chlorine in the water. Some symptoms of this include a build-up of algae and cloudy water.

Inaccurate and poor alkalinity readings 

Your pool can register inaccurate and false alkalinity readings due to high CYA. This is because it can falsely send a supply to your carbonate alkalinity which makes up all of the alkalinity.

You should balance your water according to the Langelier Saturation Index. This will allow you to know exactly where the water’s chemical levels should be. 

Lower ORP readings

ORP (Oxidation Reduction Potential) readings measure your water’s oxidizing capacity.

If too much CYA is present, you will most likely see a decreased reading with your ORP. This is because it becomes less effective and can not work as proficiently.

Various health problems 

Your health can be impacted by high CYA in your pool. It contains a harmful organism called cryptosporidium parvum which can not be properly removed from the pool’s water.

When swimming in the water, this organism can infect your gastrointestinal tract, causing digestive issues as well as diarrhea. 

Lowering cyanuric acid in your pool 

Now you know the dangers and effects of high CYA in your pool, let’s take a look at how to lower the levels to make it safe to swim in again. 

Drain and/or dilute the pool 

Unfortunately, there are no easy fixes to high CYA levels. However, draining or diluting the water is usually the best course of action. 

It is generally agreed that you need to keep your pool full to avoid it from popping out of the ground. However, you can swap the water out in portions in the form of partial drains. 

How to:

  1. Test the water to find out what the CYA levels are. This can be done with test strips, digital test kits, or liquid test kits. Knowing this will help you know how much water requires diluting.
  2. To drain the pool, you can use a submersible pump or your pool’s filtration system. A submersible pump is usually the best way to avoid damaging the pool’s system.
  3. When using a submersible pump, place it into the pool and attach a hose to it. Ensure this is long enough to reach the drainage point where the water is being emptied into. 
  4. When using the pool’s filtration system, set its valve to drain/waste/backwash. Just make sure you do not drain too much as the water level could go below the skimmer which will only take in air which will damage the pool’s system.
  5. Slowly, drain the pool just a few inches but not too much. Then, use a garden hose that is attached to your outdoor spigot and refill the pool up to the skimmer’s halfway point. 
  6. Now, retest the water and repeat this process until the CYA levels have fallen between 30 and 50 ppm.

Other methods 

You can also use a cyanuric acid reducer or specialized filters. When using an acid reducer, the pool needs to be at least 65 degrees Fahrenheit on the day before and the day of using the reducer.

Ensure the chlorine is between 1 and 5 ppm with a pH value between 7.2 and 7.6. The total alkalinity should be between 80 and 120 ppm. 

Fill a 5-gallon bucket up halfway with water and place the CYA reducer powder inside. Mix with a wooden stick. 

Slowly pour the solution around the pool close to the returns jets.

Wait around 7 to 10 days and then retest the pool for CYA levels. If they remain high, repeat the process.

In Summary 

It can take some time to learn how to lower cyanuric acid levels in your pool but once you figure out how to, it’s quite a simple process. With our methods above, you can restore your pool’s water to its former glory with ease.