Cyanuric Acid (Pool Stabilizer): Why It Matters in Desert Heat
By Imperial Valley Pool Services · Updated 2026-10-23
Cyanuric acid (CYA, or stabilizer) protects chlorine from being burned off by sunlight. Keep it between 30 and 80 ppm. Below that your chlorine disappears in the sun; above it, chlorine loses strength and the only fix is draining and refilling part of the pool.
In the Imperial Valley the sun is on your pool for most of the day, much of the year. That is exactly where stabilizer earns its keep.
What it does
Ultraviolet light breaks down free chlorine quickly. Cyanuric acid bonds loosely to chlorine and shields it, so it lasts longer between additions. It is the reason a pool with stabilizer can hold chlorine all afternoon while an unstabilized pool loses it in hours.
Why too much is a problem
CYA does not evaporate or get used up. It only leaves when water leaves, through splash-out, backwashing, or a partial drain. Many people add it again and again, in stabilized chlorine tablets and powders, until it is far above range. High CYA makes chlorine sluggish, so algae can grow even when a test shows chlorine.
Where it hides
- Trichlor tablets and pucks add CYA every time they dissolve.
- Dichlor shock adds it too.
- Plain liquid chlorine and cal-hypo shock do not add any.
How to bring it down
Drain a portion of the water and refill with fresh water, then retest. If CYA is 120 ppm and you want 60, that is roughly half the pool. Switch to liquid chlorine or a salt system so it doesn't climb again.
Our technicians test stabilizer on every visit and adjust the chlorine plan so you never end up here. See what's included in weekly service.
Frequently asked questions
What is a good CYA level for a pool in full sun?
We aim for 30–80 ppm. Pools that get strong sun all day often sit in the upper half of that range.
Can I lower CYA with a chemical?
There are enzyme products that claim to, but the dependable fix is replacing part of the water.
Do saltwater pools need CYA?
Yes. A salt cell makes chlorine, and that chlorine is just as vulnerable to sunlight. Most cell manufacturers recommend a CYA level, so follow your manual.