Water movement is very important in any aquarium. In nature, water moves. In our aquariums, we make this happen through a variety of ways. First, the proper return rate from our return pumps is necessary. I am usually happy when I am using a pump that will turn the tank's volume over 5-7 times with additional forms of water movement in the tank. Water flow is important because it moves oxygen through the gills of fish. It also moves oxygen and food to corals that are not able to move and it keeps detritus from being able to settle freely on the bottom of your tank making it difficult for some forms of algae to grow.