Domakihub Pool Stabilizer (Cyanuric Acid): What It Is and How to Use It
How cyanuric acid protects your chlorine from the sun — and the right level to keep it at.
Reviewed by Domakihub pool pros · 2026-06-23 · 4 min read
Under the strong Greek sun, chlorine burns off fast unless something shields it — and that something is cyanuric acid, the pool stabilizer. The video above shows the testing and balancing in action, while this guide walks you through what stabilizer does, the level to aim for, and how to raise or lower it. It is written for homes, holiday rentals, and hotel pools where clear, safe water can't be left to chance.
What cyanuric acid actually does
Cyanuric acid (CYA), often sold as pool stabilizer or conditioner, is a chemical that protects free chlorine from being destroyed by ultraviolet light. Without it, an outdoor pool can lose a large share of its chlorine in a single sunny afternoon, leaving the water vulnerable to algae and bacteria within hours.
It works by loosely bonding to chlorine molecules and releasing them gradually, so your chlorine lasts longer and you spend less topping it up. Think of it as sunscreen for your sanitiser — essential outdoors, but pointless indoors where there is no direct sun.
The right level — and why too much backfires
For most outdoor pools, aim for roughly 30–50 ppm of cyanuric acid; some saltwater pools run slightly higher, around 60–80 ppm. Below about 30 ppm your chlorine evaporates too quickly under sunlight, especially in summer in Greece.
Above 100 ppm you hit the opposite problem: the chlorine becomes so tightly held that it works sluggishly, a state pool pros call 'chlorine lock'. The water can test as having chlorine while still failing to sanitise. More stabilizer is not better — staying in the target band is the whole game.
How to test and balance your pool stabilizer
- 1
Test the current level
Use a test strip or liquid kit that reads cyanuric acid, or take a water sample to a pool shop. Test before adding anything so you know your starting number — guessing here causes the most mistakes.
- 2
Decide if you need to raise or lower it
Compare your reading to the 30–50 ppm target (60–80 ppm for many saltwater pools). If you are below range, you will add stabilizer. If you are well above 100 ppm, you will need to dilute. If you are already in range, do nothing.
- 3
Raise it by adding stabilizer
To increase CYA, add granular cyanuric acid or conditioner per the product dose for your pool volume. Many granular products dissolve slowly, so add via the skimmer with the pump running, and avoid retesting for 24–48 hours until it has fully dispersed.
- 4
Lower it by diluting the water
There is no chemical that removes cyanuric acid easily, so the reliable fix is to drain part of the pool and refill with fresh water. Drain and replace in stages, retesting as you go, until you bring the level back under 100 ppm.
- 5
Recheck and rebalance the rest
After adjusting stabilizer, retest CYA along with chlorine and pH, since changes here affect how your chlorine behaves. Re-test stabilizer every few weeks in peak season, and after heavy rain, big top-ups, or a partial drain.
Rather have a pro handle it?
Get a vetted pool pro in your city — one number, booked in EN/EL/DE.
FAQ
- What is the ideal cyanuric acid level for a pool?
- Around 30–50 ppm for most chlorine pools, and roughly 60–80 ppm for many saltwater pools. Below 30 ppm your chlorine burns off too fast in the sun; above 100 ppm chlorine works poorly and may stop sanitising effectively.
- Do indoor pools need cyanuric acid?
- No. Stabilizer only protects chlorine from UV light, so an indoor pool with no direct sun gains nothing from it. Adding it indoors just risks over-stabilising the water and slowing your chlorine down.
- How do I lower cyanuric acid if it is too high?
- The practical method is dilution: partially drain the pool and refill with fresh water, repeating in stages while retesting until you are back under 100 ppm. There is no simple additive that removes it, so prevention and correct dosing matter most.