In the reef tank, the most common type of water movement is called laminar flow. This simply describes the flow of water in one direction. In the ocean, laminar flow is usually found in the deeper parts of the reef at depths of 50 feet or more. However the coral kept in a reef aquarium are naturally found in the shallower areas of the reef at depths less than 40 feet. This being the case, the best types of water movement for corals in a reef tank are surge and turbulence. We offer a number of different Submersible Circulation Pumps you can use in your reef tank to create natural water movement which will be very beneficial to your reef tank.