If you are a diver don't overlook this trick if you are ever faced with an emergency aeration problem due to a pump failure or poweroutage...
You can rig a device that will aerate your reef tank from one of your SCUBA cylinders...
"...Using the first stage from an old regulator, the LP hose can be attached to a needle valve that can handle the rated pressure of around 150 psi. From the needle valve, a standard aquarium airline runs into the tank ending with an airstone. Simply cracking open the SCUBA tank valve will aerate the aquarium for at least two hours. Periodically closing the valve can extend the life of the air in the cylinder ten-fold. Anyone with access to a medical or welding oxygen cylinder can rig a similar, but much more effective aeration system..." (Adv Aqrst)
More insurance....
FYI