If you don’t know what the old paint is, you can scrape off a few chips and have them tested at a local paint store or send them out to a manufacturer. Pool paints start at about $50 per gallon for acrylics and about $100 a gallon or more for epoxy. A gallon should yield one coat of 100 square feet.
While a plaster finish is more expensive than paint, it offers ample protection and a classic look for your pool. Most pool plaster is made of cement, sand, and water, while some higher-end mixtures include marble aggregate. It’s relatively easy to refinish a medium-size pool with plaster for around just $7,000-$10,000 and up, but keep in mind that the coating requires frequent maintenance.
Retiling is another option to revive your pool. This is the same procedure as indoors. The pool is given a scratch coat, then tiles are laid and grout is placed in between. Tiling can be expensive and time-consuming depending on the size and complexity of your pool. However, it will result in an elegant look.