Cyanuric acid forms with a triazine derivative a fine precipitate. The turbidity caused by this reaction can be measured visually or photometrically to determine the cyanuric acid concentration.

Chlorine for disinfection in swimming pools, is degraded by intensive UV radiation. A common stabilizer for chlorine in swimming pools is cyanuric acid. Chloroisocyanic acid is also used directly as disinfecting agent. Forced by legal regulations, or because of their personal interest in a good state of their pools, many private and public owners use rapid tests for frequent monitoring of cyanuric acid.