National Pool Opening Day is a popular holiday that Americans celebrate on the last Saturday in April. This year, it takes place on April 29. Because swimming makes summers memorable, pool owners must keep them clean and ensure they’re safe for pool parties with family, neighbors, and friends. Besides providing a place to socialize, swimming pools also encourage physical activity. By keeping your pool’s acidity and alkalinity levels in check, you ensure that it’s ready for you to enjoy a swim throughout the summer.