Air pumps are an important part of any complete tropical fish habitat. Air pumps can power air stones, bubble walls, CO2 diffusers for aquatic plants, moving decorations and undergravel filters. Traditionally, air pumps are also the noisiest part of an aquarium set-up--especially older models. Thankfully, there are simple ways to reduce noise from your fish tank's air pump.
The first step in eliminating noise from an aquarium air pump is to determine where the noise is actually coming from. Noise from a fish tank pump will usually be in the form of buzzing, rattling or humming. These noises are caused by vibrations.
Lift up the pump. Does the noise stop? If so, the pump is vibrating against the surface it is resting on. Skip to Step 4.
If the noise does not stop when lifting up the pump, apply pressure on the plastic outer casing of the pump. Try each side, applying varying amounts of pressure with your finger. Does the noise stop? If so, the pump's outer casing is loose or faulty. Skip to Step 5.
If neither lifting nor applying pressure to the pump does anything to stop the noise, the inner workings of the air pump are faulty. In this case, the sound will typically be an electrical humming or harsh, intermittent buzz. Although similar to the sounds produced by mechanical vibration, the sounds associated with imminent electrical failure are generally distinct. The failure of an electric pump can cause a surge on the circuit its connected to, or could even be a fire hazard. You should unplug the pump immediately and replace it whenever possible.
If you've determined that your noise is caused by the pump vibrating against the surface it rests on, check if your pump has brackets on the bottom for screws. This makes it easy to secure a pump to a flat surface tightly. If your pump does not have screw eyelets, or you don't want to damage the surface by screwing into it, you can dampen the vibration significantly by placing a foam mat or section of foam shelving paper between the pump and the hard surface.
Most modern pumps are single plastic-moulded units. Some other pumps are assembled with bolts. First, tighten any bolts or screws that exist on the surface of the pump. If this does not tighten the pump's outer casing enough to stop the noise, begin putting rubber bands around the unit. Choose rubber bands that fit around the unit as snugly as possible. Continue adding rubber bands until they have compressed the unit's outer shell significantly enough to reduce the vibration noise.
Never work with electronics around water. If your aquarium area is damp, dry it off well before doing any sort of work with your pump.