What does pool stabilizer do? The answer is both simple and (chemically) complex at the same time, so in this blog, we’re going to help break down why the pools you’re managing likely need pool stabilizer, how it works and what it does, when to add it and how to add it safely, and how to test for pool stabilizer levels.
What Pool Stabilizer Does and Why You Need It
Pool stabilizer is also referred to as pool conditioner or chlorine stabilizer and is most commonly cyarunic acid, or CYA for short.
When you add unstabilized chlorine to your pools alone, the sun can actually degrade up to 90% of the free chlorine levels within just a few hours. It also dissipates faster and provides weakened sanitizing power.
However, you can easily use CYA as a buffer to stabilize, or condition, the chlorine and prevent the sun from eating it up so quickly.
The CYA binds to the chlorine molecules and forms a protective layer around them, while still allowing the chlorine to effectively sanitize pool water.
This also helps ensure the chlorine you’re adding can effectively do the job it’s meant to do–sanitize the pool water and keep swimmers safe–and it also helps control your chlorine usage throughout the pool season, keeping chemical costs down.
Typically, pool stabilizer is only required in outdoor pools, unless your indoor pool receives a large amount of direct sunlight through windows or skylights.
When Does Pool Stabilizer Need to be Added?
There are two ways to add pool stabilizer to pools: you can simply use stabilized chlorine, which is chlorine that has the CYA already added to it, or you can add unstabilized chlorine, like liquid chlorine, and CYA separately. Let’s look into the pros and cons of each approach.
When you add stabilized chlorine, it has the benefit of containing both chemicals together, which certainly makes the process more convenient.
However, over time, the chlorine gets used up and you’ll need to add more, but the cyanuric acid does not. CYA stays in the water and every time you add more stabilized chlorine, its levels add up until it “locks up” the chlorine. Over time, it will take more added chlorine to reach the same level of sanitizing ability.
What chlorine lock means is that too much of the chlorine is bound to the CYA, which freezes it so it is unable to do its job of sanitizing the pool water–leaving the water and your swimmers vulnerable to bacteria, algae, viruses, and more.
The easiest way to resolve chlorine lock is to completely drain the pool and start over with new water and chemicals, which is expensive, time-consuming, and causes downtime for your pool, costing you business.
Conversely, adding unstabilized chlorine and then adding CYA separately will give you more control over the water’s CYA levels, and help keep your chemical costs down.
Typically, when you go with this method, you can expect to add pool stabilizer once, at the beginning of each swim season. It’s possible that you may need to add it again, following large pool parties, record swimmer days, for example, on summer holidays, swim meets, requiring added water, or large rains, which can dilute pool water chemicals.
Which brings us to our next point, the importance of testing CYA levels periodically throughout the season.
Testing Pool Stabilizer Levels
For chlorine pools, you should aim to keep pool stabilizer levels below 50 ppm. Anything above 50 ppm, the CYA starts interfering with chlorine’s sanitizing power, can lead to chlorine lock, and, as an acid, can even damage vinyl pool liners. Pools using stabilizer are required to keep their free chlorine levels above 2.0ppm. Hot tubs and therapy pools should not use stabilizer due to the higher temperatures reducing the effectiveness of the chlorine.
No matter which type of pool testing kit you’re using, you should ensure it includes cyanuric acid as one of its parameters. Depending on your state and local regulations, as well as pool visitor volume, you can expect to test for CYA levels anywhere from weekly to monthly. In our opinion, more frequent testing can make it easier to ensure your pool water levels are safe and balanced, your chlorine is still able to sanitize effectively, and you’re not overusing chemicals and adding to your costs. Thankfully, most digital pool test kits make this fairly quick, easy, and accurate.
How to Safely Add Pool Stabilizer
Just like muriatic acid, cyanuric acid is, well, an acid, and should be handled carefully and safely as such.
Cyanuric acid is available in either liquid or granular form. Whichever you use, ensure you store it in the manufacturer's packaging, follow manufacturer directions for storage, keep away from direct sunlight, protect from extreme temperatures, off the ground, and away from potential exposure to moisture or water. It’s also always a good practice to keep a laminated copy of the chemical’s safety data sheet posted by the chemical, so it’s readily available for your staff adding the stabilizer to the pool.
After you’ve tested CYA levels, add the correct dosage of cyanuric acid to a bucket of warm water to dissolve. Even if the manufacturer states it can be added directly to the pool, adding it first to a bucket of water will minimize the risk that it will splash or spill on you or your staff, causing skin irritation and other damage. This will also help reduce the risk of damage to your pool lining.
Once it’s dissolved in the bucket of water, it can be added to the pool water on the edges. Use a brush to effectively mix it throughout.
Final Thoughts on Pool Stabilizer
No matter if you’re managing pools on hotel or apartment properties, at an HOA community, or a typical commercial or public pool, it’s always a good idea to employ a Certified Pool Operator on staff who is trained in pool chemical safety and calculations. Often this is required by the local health department to operate the pool.
Even still, the calculations to keep CYA and free chlorine levels correct and in scale can be complex and time-consuming. It’s why we built the Pool Shark H2O app: instantly, it does all the chemical calculations for you, telling you exactly how much CYA and other chemicals to add, ensuring safety, balanced water, and lower chemical costs.
When paired with the LaMotte Spin Touch, testing is complete within 60 seconds to a high degree of accuracy.
Tests and chemical logs are also digitally recorded and locked, setting you up for easy Health Department compliance, and making it easy for managers to check tests, logs, and alerts remotely, for multiple properties.
