Most older pools in Florida were originally finished with Marcite. Marcite is a mixture of white Portland cement, marble dust, and fortifying additives to boost strength and water resistance. Old Marcite pools generally last 10 to 15 years.
Today marcite finishes are not considered what they once were. The longevity of marcite has changed dramatically. It has gone from having an average life of 10 to 15 years to now averaging about 5 years.