There is no definitive answer to this question as it depends on a number of factors, such as the size and depth of your pool, the climate you live in, and how often you use your pool. However, a good rule of thumb is to aim for a pump that can circulate at least half the volume of your pool every hour. For example, if you have a 24,000 gallon above ground pool, you would need a pump that can circulate at least 12,000 gallons per hour.