To close loop or not to close loop is one question serious reef geeks try and consider. If you have the luxury, a closed loop system is a fantastic way to handle flow in the aquarium without having to have the lovely powerheads all over the place. For public aquariums with hundreds of thousands of gallons, a closed loop is not an option, its a necessity. This amazing picture by the Steinhart Aquarium at the California Academy of Sciences in San Francisco puts large-scale flow in perspective showcasing the 3 40 horsepower jet pumps that supply the five different and controllable flow zones in the 212,000 gallon Philippine Coral Reef display.
[Image via Steinhart Aquarium and Richard Ross]