Plaster is the most economical choice in the short run, as it is made from a mix of cement, white sand or marble aggregate and water. Most people choose white plaster, but it can be dyed the color of your choice. Plaster is economical, classy, and simple; however, you can expect to resurface the pool within about 7 years. Pool plaster can be rough and does allow algae to grow. Regular maintenance is needed, along with acid washing every 3 to 5 years.