Effects of Cyanuric Acid
When maintaining pools, cyanuric acid (CYA) is a key ingredient for pool maintenance and allows your pool to remain chlorinated in direct sunlight and will keep chlorine active in your pool. Without CYA, the chlorine will quickly dissipate and leave your pool unprotected. While, CYA provides many benefits for the pool industry and the typical pool owner, having high levels of CYA can also cause damage and cause the chlorine to be less effective. CYA needs to be regularly diluted with fresh water, and if not, CYA can rise to high, unwanted levels, beyond the standard 30-50 ppm. Having an increase in CYA can cause a number of chemistry problems such as skewed alkalinity readings, low ORP readings, and inefficient chlorine. In addition, having large quantities of CYA can cause damage to plaster which is why it’s essential to understand the effects and consistently monitor CYA levels.
Adjusting Total Alkalinity to Carbonate Alkalinity
When high CYA is present, a significant portion of the CYA affects the total alkalinity readings. This must be adjusted for, when using the saturation index to determine water balance. This is done by subtracting approximately 1/3 of the CYA (in ppm) from the total alkalinity (in ppm), to arrive at the carbonate alkalinity. If this adjustment to the carbonate alkalinity is not made, and instead, the total alkalinity measurement is used, the water will be in a more corrosive condition than the saturation index calculation states. In other words, it will give you a false indication that the water is balanced, when in fact, the water is in a corrosive condition.