For a quiet pump without the loss of power, a whisper pump is perfect for reducing noise levels produced from air pumps.
Things to Consider:
Sleeping Areas -- If your aquarium is in a bedroom, you might not enjoy the vibrating noise or rough currents of an air pump. With a whisper pump, this noise will be eliminated.
Perfect Size -- Whisper pumps come in a number of sizes based on the amount of water in your tank. Select the one that fits your aquarium best.
Indoor/Outdoor -- Be sure to check if your pump is safe for outdoor use, if you plan on using it for a fountain. Some are temperature-sensitive and need to be kept indoors.