Ideal pool cyanuric acid range
What is Cyanuric Acid?
Cyanuric acid, also called stabilizer or conditioner, shields chlorine from breaking down under UV sunlight so it lasts longer in outdoor pools.
Why it matters
Too little CYA lets sunlight burn off chlorine within hours; too much is widely associated with "chlorine lock," where chlorine becomes far less effective at killing bacteria and algae even at a normal ppm reading.
How to raise CYA
Add a stabilizer/conditioner product through the skimmer and let it dissolve fully before it reaches the pool — undissolved granules can bleach vinyl liners.
How to lower CYA
Partially drain and refill with fresh water; cyanuric acid doesn't break down on its own and there's no chemical treatment that removes it.
How often to test
Monthly, or more often if using stabilized chlorine products (dichlor/trichlor) regularly, since they add cyanuric acid with every dose.
Get the exact dose to bring CYA into range for your pool's volume — free, instant, no sign-up.
Related parameters
Track this with Skimmer — log water tests and keep every reading in one place.
See pricing →