Water Movement

Water Motion in Reef Aquariums

Corals are simple creatures with limited ability to feed, reproduce and rid themselves of waste. Water movement is key to the success of the reef tank with each type of coral requiring different flow rates. Mushroom Coral requires little flow while many species of Acropora thrive under much more turbulent conditions in the range of 30 to 40 times more flow most likely due to their proximity to wave crests in the wild.

In nature, corals and other reef inhabitants are accustomed to rapid, constant water movement, and have evolved physiologically to benefit from it. Water movement is important for several reasons:

Growth - Water currents in aquariums bring corals, clams, and sessile invertebrates the food, oxygen, nutrients and movement necessary to stimulate growth.
Waste Removal - Currents "clean" corals by carrying away waste products and sediment that promote damaging algae growth.
Fish Health - Strong current demands increased movement among fish, and helps them burn off excess fat found in many commercial fish foods.

Of the many different types of creating this needed water flow the most popular method is by using multiple power heads which are simply small submersible water pumps. The pumps are randomly switched on and off using a wave timer. Each aimed at the flow of another power head or at the aquarium glass to create a random flow in the tank. Another method gaining popularity is the closed loop by which water is siphoned from the main tank to a pump that in turn pushes the water right back into the aquarium via multiple returns to create water turbulence.