The Center for Disease Control and Model Aquatic Health Code advises hot tub and spa owners not to use products containing Cyanuric Acid. This is due to the alarmingly increase in reported cases of waterborne illness. Along with unsafe and costly water chemistry issues.
What is CYA?
CYA is an abbreviation of Cyanuric Acid. CYA is also referred to as Stabilizer. You will find that trichlor and dichlor products contain Cyanuric Acid, which protects chlorine from degradation due to sun exposure. If it's used correctly and maintained at a low level, CYA can be beneficial in pools and spas.
Research has proven that high levels of CYA results in a condition known as Overstablization. It compromises the water quality, integrity of surfaces and equipment and puts the safety of swimmers health at risk.
The Facts:
When the water has a CYA level that is 50PPM or more; problems begin. The strength of chlorine decrease making it only 1/3 effective and it takes 4 times longer for chlorine to kill bacteria, viruses and pathogens.
Overstabilization can cause damage to surfaces and equipment along with reducing the life expectancy resulting in costly repairs.
Temperature of the water can affect the CYA reading. If it's greater than 90 degrees the CYA will test 15PPM lower than what it actually is. If the temperature is less than 60 degrees it will test 15PPM higher.
DiChlor is about 50% Cyanuric Acid by weight. More than half of every tablet of stabilized chlorine is actually Cyanuric Acid.
High CYA levels can cause inaccurate alkalinity and pH readings.
Overstabilization can force homeowners to drain and refill their pool or spa causing huge costs. In some states draining chlorinated water is prohibited by law.
Prevention
Do not use products containing Cyanuric Acid. Spa products containing NO Cyanuric Acid are listed below. Have your water professionally tested and read handling instructions on the back of chemicals.