Answer: 40 - 80 ppm
Explanation: The recommended level of cyanuric acid in a traditional chlorinated swimming pool is typically between 30 and 50 ppm (parts per million). Cyanuric acid acts as a stabilizer, helping to protect chlorine from being degraded by sunlight. Maintaining levels within this range ensures effective sanitization while minimizing chlorine loss. Regular testing is important to monitor and adjust cyanuric acid levels as needed.