Social & Preventive Medicine Which of the following is not a recommended sanitation measure for swimming pool sanitation? A Recommended area per swimmer = 2.2 per sq. meter B water to be refiltered in less than 6 hours (rapid sand filters) C Residual level of free chlorine to be >0.5ppm D 15% water to be replaced by fresh water every day 💡 Explanation Which of the following is not a recommended sanitation measure for swimming pool sanitation? ✓ Correct Answer: C. Residual level of free chlorine to be >0.5ppm