Acid washing removes a thin layer of your plaster, gunite, or Pebble-Tec to reveal a fresh surface. This removes algae, mineral, chlorine and even dirt stains from the bottom and sides of your pool. If your pool was poorly maintained in the past or has had stagnant water which turned into an algae bloom, algae and phosphates can become embedded in your pool’s finish, making it nearly impossible to get rid of. Acid washing your pool removes any algae or phosphates that are not otherwise removed with chemicals. When finished, the acid washing process gives your pool a clean, fresh new finish, and clear sparkling water.