<prompt> Which of the following is not a recommended sanitation measure for swimming pool sanitation?Recommended area per swimmer 2.2 per sq. meterwater to be refiltered in less than 6 hours rapid sand filtersResidual level of free chlorine to be 0.5ppm15 water to be replaced by fresh water every day  <response>: SANITATION MEASURES FOR SWIMMING POOL SANITATION: Recommended area: Recommended area is 2.2 sq.meter 24 sq.ft per swimmer Surveillance: Rules and regulation to be posted in appropriate place Filtration of water: Water to be refiltered in less than 6 hours rapid sand filters; 15 water to be replaced by fresh water everyday Chlorination of water: Residual level of free chlorine to be 1.0 ppm to protect against bacterial and viral agents pH of water: 7.4-7.8 Bacteriological quality of water: To be as close to standards prescribed for drinking water. Ref: Park 25th edition Pgno: 765 