What is Acid washing? Why do concrete pools require an acid wash?

Every 5 years, or sometimes less a concrete pool will require a complete cleaning.  This typically is done when the pool is drained and a mild acid detergent is scrubbed into the walls and floor.  This removes any build-up of algae that might be lingering around in your pool.  Acid washes decrease that chance that you will have an algal bloom occur in your pool.