How To Choose an Aquarium air pump
Aquarium air pumps were once used primarily as the device to power under-gravel filters for aquariums. Today, however, although under-gravel filters are still sometimes used modern internal and external power filters have largely replaced them and the air pump is used for other purposes.

What is an aquarium air pump?
An aquarium air pump is a device which sits external to the aquarium and when plugged into the mains electrical supply will pump air from itself to a device connected to it. The air is produced by a diaphragm inside the pump which vibrates many times a second to produce a continuous air output. The vibrating effect produces a buzzing noise which can be annoying. Cheaper brands of pumps tend to produce more noise. Lifeforce stock the Rena range of air pumps which are probably the quietest available at the moment but you should bear in mind there is no such thing as a silent air pump. The Rena range is made up of five models, the Rena Air 50, 100, 200, 300 & 400. If even the modest amount of noise produced by these pumps is too much for you or you have an older or cheaper model, you can, providing the pump is powerful enough to deliver air over a distance, site it remote in a cupboard or even another room. Remember though, the air pump has to be sited outside the aquarium, NEVER submerse one in the aquarium water or position where it could get wet. Air pumps have one or more outlets from which to deliver the air supply.

Uses for an aquarium air pump.
Air pumps can be used for a variety of applications. Some basic, non-powered Protein Skimmers need an air pump to supply a powerful delivery of air to the skimmers wooden diffuser. Only good quality, powerful pumps are suitable for this application.

By far the most common use is to produce a decorative effect. A length of airline (Available in pre- cut lengths of either plastic or silicone airline. Silicone type does not harden with time as does the plastic type and can help make the pump quieter although is a little more expensive) connects to the pump outlet and is attached to an item such as a bubble wall or airstone which are positioned inside the aquarium. An attractive curtain or stream of bubbles is produced as the pumped air is diffused through these items. There are many different types and sizes of airstone and bubble walls including round and flexible ones. The larger the air pump the greater the effect or number of items that can be used. Position an airstone inside a rock cluster or ornament for an attractive effect. Underwater action ornaments are also available which become animated in some way when the air supply is connected. These can be great fun, especially for the younger fish keeper.

One practical use for an air pump is to increase the oxygen levels in an aquarium. Most modern aquarium systems should not become oxygen deficient but for various reasons, it can sometimes happen. The most common types of aquaria that tend to develop low oxygen levels are un-filtered coldwater systems, those that are overstocked or have particularly large fish in them, those that have a higher than average or desirable temperature or when maintenance has been badly neglected. Indications of a low oxygen content are when the fish can be seen gulping at the surface as they try to take atmospheric oxygen over their gills. Rapid gill movement (Which can also be a sign of Ammonia poisoning or stress) at any level in the water can often be an early sign of dropping oxygen levels. In these cases an air pump is an invaluable device for ensuring the survival of your fish. Air from the pump does not directly diffuse into the water but as the vigorous stream of bubbles breaks the surface, surface film is dissipated and surface area is increased allowing greater oxygen absorption.

Maintenance of aquarium air pumps.
Aquarium air pumps usually have quite a long life and require little in the way of maintenance. Carrying out a few basic tasks will ensure that you get maximum life from the unit. Firstly, airstones should be replaced every 10 to 12 weeks as they clog up with fine debris. When clogged back pressure builds up in the pump which can damage the pump diaphragm and motor unit. Bubble walls and flexible air curtains tend to have a longer life than ceramic or wooden air diffusers and some types can be cleaned and re-fitted. Secondly, it is important to replace the air filters if fitted (Small white cotton pads through which the air is drawn from the atmosphere into the pump). These too become clogged, particularly in a smokey environment, and then make the pump work harder. Regularly check airline for kinks as these too will cause back pressure. Finally, if the air supply does appear to decrease the diaphragm may have split. These can usually be obtained quite cheaply either individually or as part of a maintenance kit and are easily fitted so restoring the pump to its previous performance.