There are many differences between a pool and a spa, not only in the size and the temperature of the water, but also in the type of care and maintenance needed. Sanitation, chemicals, and maintenance are important in spas because the accumulation of waste and the breakdown of chemicals is much faster than in pools, due to a higher evaporation rate and heavier usage. Imagine that the equivalent of four people in the average spa is the same as three-hundred people trying to swim in the average pool. Therefore, it is important to set up a program of weekly maintenance for your spa. This should include the use of a test kit to measure the proper balance of chemicals such as chlorine (KLOR-een) or bromine (BRO-meen), as well as the alkalinity, and the degree of acid or base in the water. It is also recommended that you change the water in your spa about every three months. For more information on proper spa maintenance, contact a pool and spa supply company in your area.