Three busy indoor swimming pools in Kowloon Park were closed for 10 days from yesterday because of small red worms found in the water. Only a day earlier, officials of the Leisure and Cultural Services Department insisted the worms were not a threat to public health and there was no need to close the pools. Secretary for Home Affairs Patrick Ho Chi-ping said yesterday that the pools were being closed to alleviate public worries, but he still insisted that the water remained safe. He said the department would step up measures to ensure swimmers at public pools maintained good personal hygiene, for example by showering before swimming and wearing swimming caps over long hair. Closure notices were posted at the entrance of the Kowloon Park indoor swimming pools before their scheduled opening time of 7am yesterday. Assistant director of leisure and cultural services Paul Cheung Kwok-kee told a media conference the decision to close the swimming pools was made out of a 'responsible and cautious manner' after the department failed to identify the source of the red worms. 'The water supplies department has confirmed that there is no problem with the water quality,' he said. 'However, we have observed red worms over the past few days that create anxiety among swimmers. 'We still do not have a clue where the worms come from. So we believe the solution is to entirely empty the pools and stop the operation of the sand tank and the filtration system.' According to the department, red worms were found only in the leisure pool but the department decided to close the main pool and the diving pool as well. About 5,500 swimmers a day used the seven swimming pools in Kowloon Park last month. Mr Cheung said the department stepped up cleansing after it received a report of red worms on August 4. It did not spot any red worms until August 17. 'We decided that we should close these pools so we can do a more thorough check on the sterilisation system,' he said. Stephen Chan Hung-cheung, assistant director of electrical and mechanical services, said water, sand and acid carbon in the swimming pools would be replaced. Kwok Yau-ting, senior chemist of the water supplies department, said the leisure and cultural services department regularly took samples from public swimming pools inspections. The department received eight water samples from different swimming pools on August 19 but testing showed that the water remained at a safe level.