What Cyanuric Acid Does in a Pool
Cyanuric acid, also called stabilizer or conditioner, is one of the most misunderstood readings in pool chemistry. It is essential in a sunny climate and destructive in excess, and most homeowners have never had it tested.
What It Does
CYA bonds loosely with chlorine and shields it from ultraviolet light. Without it, unprotected chlorine in direct Bakersfield sun can be largely destroyed in a matter of hours. With a reasonable level present, the same chlorine lasts through the day, which is why unstabilized pools in this climate are nearly impossible to keep sanitized.
Why Too Much Is a Problem
That same bond that protects chlorine also holds it back. As CYA climbs, a progressively larger share of your free chlorine is bound and unavailable to sanitize. At high levels the water tests as chlorinated while behaving as though it is not — algae grows, chlorine demand seems bottomless, and shocking produces disappointing results.
Why It Keeps Climbing
- Trichlor tablets and dichlor granules add CYA with every dose
- Evaporation removes water but leaves CYA behind
- Topping off replaces the water, not the balance
- Nothing in normal pool operation consumes or removes it
How It Is Corrected
Dilution. Replacing a portion of the water proportionally reduces CYA — replace a third of the water and you remove roughly a third of the stabilizer. Products claiming to reduce CYA chemically have not, in our experience, produced reliable results on real pools. After a partial drain, switching to an unstabilized chlorine source keeps the level from climbing straight back.