How Does Cyanuric Acid Work?
Pools with very low or no CYA will have significant chlorine demand. This is because unstabilized chlorine is destroyed by UV rays very quickly. This leaves your pool vulnerable to contaminants unless you continually add more chlorine.
Instead of making chlorine upkeep your full-time job, add cyanuric acid instead. Once the chlorine in your pool water has transformed into sodium hypochlorite ions, the CYA binds to those ions, preventing them from breaking apart when exposed to UV rays.
This is how it preserves your free chlorine and allows it to destroy bacteria three to five times longer than it would without cyanuric acid.
That extra time is especially important because at the same time CYA stabilizes chlorine, the bond between cyanuric acid and sodium hypochlorite ions also hinders chlorine a bit.
The Downside of Cyanuric Acid
Chlorine’s ability to effectively sanitize is called oxidation reduction potential (ORP). This figure, measured in millivolts, is important because it shows you how well your free chlorine is working. Cyanuric acid reduces chlorine’s ORP, regardless of how much of it you put in your pool.
But if you add too much CYA, or allow cyanuric acid levels to get too high, you’ll completely obliterate the chlorine’s effectiveness, meaning you’ll have wasted money on two chemicals and still have a dirty pool.
You need your chlorine to stick around, but you also need it to destroy contaminants quickly enough to keep swimmers safe. In order to do both, you’ll have to strike a balance between appropriate free chlorine levels and CYA.
To increase CYA levels, all you need to do is add some. Once you’ve added the proper amount, you won’t need to add it regularly because the chemical remains in your water at fairly consistent levels over time.
Dilution is really the only thing that will result in lower levels, so be sure to test levels after, say, a rainstorm.
Ideal Cyanuric Acid Levels
The World Health Organization recommends an upper limit of 100 parts per million (ppm) of cyanuric acid in a swimming pool. They arrived at this number based on the assumption that children will likely swallow some water while swimming, and if they ingest too much CYA, it can make them sick.
We recommend keeping your cyanuric acid around 50 ppm. Aside from safety concerns, any higher concentration will inhibit your chlorine enough to chance algae and bacterial growth. Remember, more CYA doesn’t necessarily mean more protection from UV rays.
If your pool’s cyanuric acid level is over 50 ppm, you may notice algae growth, some difficulty maintaining balanced chemistry, cloudy pool water, and decreased sanitizing.
If your level climbs above 100 ppm, you may not even be able to read the exact amount on a test strip. In this case, take a sample in to a pool supply store for more accurate testing before you act to lower the CYA level.
How to Lower Cyanuric Acid Levels
When you test your pool water, if you find the CYA levels are too high, the first step is to troubleshoot.
Check to see whether you’re using stabilized chlorine, which already contains small amounts of cyanuric acid. If you see these chemicals listed on the label, your chlorine contains cyanuric acid:
• potassium dichloroisocyanurate
• sodium dichloroisocyanurate
If you find this is the issue, switch to chlorine without CYA added to it to prevent levels from rising again.
However, you still need to lower the cyanuric acid level to keep your chlorine working as it should. If the CYA levels that are more than just a little high, diluting your pool water is the only way to lower them. Allow splashout to bring down your water level, then top off your pool with fresh water.
If the levels are extremely high, you may need to drain your pool and refill it with fresh water. Be aware that the chemical can hang around in your filtration system, so if extremely high levels are a problem, you may want to backwash or change your filter.
Cyanuric acid has also been found in pool plaster and in calcium scale. If your levels climb rapidly after a refill, lingering CYA could be the problem.
A Note About Cryptosporidium
You will also need to lower cyanuric acid levels if your pool is contaminated with cryptosporidium.
Also referred to as crypto, this parasite can cause respiratory and gastrointestinal illness, and is typically introduced to pool water through feces. It’s a common problem in public pools and splash pads where babies go into the water with diapers not made for swimming or splashing activities.
Crypto is resistant to normal chlorine levels, and contamination requires imm
Post time: Feb-11-2021