Stabilizer

Stabilizer and cyanuric acid mean the same thing. You may also see it called conditioner or CYA on products and test kits.

Its job is to hold chlorine in the water longer when the sun is hot. In North Texas summers, an unstabilized pool can lose chlorine within hours. But stabilizer builds up from tablets and dichlor, and it never burns off. If chlorine keeps testing low even after you add more, test stabilizer first. A high reading often explains it. See chlorine lock for the next step.