Depending on the size of the pool, reattaching all the pool equipment, removing the cover and balancing the water can take up to a week. After the filter and pump are working again, be sure to scrub the walls and floor to remove any algae that grew over the winter.
During the swim season, test the water to stay at a pH of between 7.2 to 7.6 and a residual chlorine level between 1 to 3 parts per million. Chemicals are best added in the evening after everyone is done swimming so the chemicals can work overnight.
Winterize the pool to prevent the water lines and filters from cracking when frozen. Use a winter cover that can withstand snow and ice without tearing. Winterizing chemicals, added just before the cover is put in place, keep the chlorine level high enough to kill contaminates while the pool is not in use.