Listed above is a chart to help you select the correct size pump for your needs. The following information may also be of help:

The Rio 50, 90, and 180 are most often used for table top fountains. The Rio 400 and 600 are perfect for small aquariums and larger fountains. The Rio 1100 and 3100 are great for aquarium or pond use. These pumps may also be used with the Rio Pro Filter and/or Rio Large Fountain Heads.

To assess your aquarium needs you should consider a pump that circulates 4 times the tank volume for freshwater and 5 times for salt water. The use of filters, or when bringing water up for than 1 foot, will begin to reduce the total GPH flow and should be considered. Pond circulation should be 2 to 3 times the volume for a small pond. Larger ponds shoudl have acirculation as close to the total volume as possible. All Rio pumps come with a flow control valve that allows you to adjust the output to meet the needs of your water project. The table above will help you select the Rio Pump to meet your needs.