Aquarium air pumps are widely used to drive filters, bubblers, and other equipment. I'm often asked where an air pump should be placed. Does it really matter? The answer is yes placement does matter. There are places that are good and some that should be avoided.

Never Below Water Level
Possibly the worst possible place is the one many people choose - the cabinet underneath the aquarium. Placing an air pump below the water level of the aquarium is a recipe for trouble.

Air pumps should always be placed well above the water level in the tank. Unfortunately that isn't always easy to do, because it's harder to conceal an air pump when it can't be placed below or even behind the tank.

However, there's a good reason to resist the urge to stuff the air pump in that very inviting cabinet below the aquarium. There's a little thing called gravity, and it's not to be trifled with. If the power ever goes out or the pump stops functioning for any reason, gravity will kick in causing water to begin siphoning down from the tank through the air pump. Not only will that destroy the pump and cause water damage to the surrounding area, but it also presents a risk of electrical shock.

Even if the power never goes out, and the pump always runs normally, placing the pump below the water level puts back pressure on the pump. That extra pressure often causes the pump to run louder, and nobody wants a noisy air pump. So where is the best place to place an air pump?

Shelves or Hooks
Ideally the air pump should be placed well above the water level in the tank.

Never place an air pump on top of the tank itself. The vibrations from the pump are not healthy for the fish, and there is always a risk of the pump falling into the tank. If the pump is placed on a shelf, make sure the shelf has a lip to keep the pump from sliding off. The shelf should not be connected to the tank in any way, as it would transfer vibrations to the tank. It is also possible to hang the pump on a hook, however make sure the hook is very secure so there is no risk of the pump falling.

Muffle It
Another tip when placing an air pump is to sit it on a sponge or cloth to dampen the noise. An old handkerchief or sock works nicely for this purpose, and costs nothing. Some take the extra step of placing the entire pump inside of a cardboard box, with a cloth underneath the pump itself. I’ve seen some creative people have their kids decorate an old shoe box for this purpose. Then they padded the bottom with old socks, and voila, peace and quiet.

Check Valve
Lastly, in addition to placing the pump above the water level, it is also wise to take the extra step of placing a check valve in the line. A check valve is an inexpensive insurance policy to prevent water from siphoning backwards into the pump.