Fresh air in the aquarium: Air pumps

There are often discussions going on about technical aquarium equipment: about choosing the correct filter, suitable (LED) lighting or the best heater. There are – especially on the Internet – also different views concerning using air pumps. It is this difficult to find clear and well-founded advice, especially for beginner aquarists. The answers to the most frequent questions are compiled in this contribution.

What are air pumps required for?

Fish, other aquatic organisms and plants require a certain amount of oxygen in the aquarium water, which they take up via their breathing organs or the surface, respectively. There are two possibilities how oxygen gets into the water in a natural way: it diffuses into the water via the water surface, which is enhanced by surface agitation. Additionally, the aquatic plants produce oxygen during photo synthesis. The oxygen requirements of the fish is different between the species. Enough aquatic plants and possibly a suitable aeration system should be present when keeping fish that require water particularly rich in oxygen. Good aeration is also required if the fish are ill and need to be treated with medications: Medications often do not only remove pathogens, but also harm useful bacteria. The resulting decomposition process consumes additional oxygen. Several water care products should ideally also be used with good aeration. The temperature also influences the oxygen level: it can get dangerously low during summer due to the heat. Using air pumps is advisable in the mentioned cases.

How do air pumps work?

A membrane pump (e.g. sera air 275 R plus), an air hose and an airstone are required for providing a sufficient oxygen level. The rocker arms, on which the membranes and small permanent magnets are attached, move in the magnetic field of an electromagnet. The membranes move up and down at 50 Hz AC and intermittently press air towards the membrane block outlet, where the air hoses are connected. Prefiltered air is pressed into the outlet through the felt of the membrane block. This movement takes place about 1.5 billion times a year per membrane. For comparison: the human heart beats about 2.6 billion times up to an age of 90 years. The higher the current provided, the stronger the swept volume of the membranes and, correspondingly, pump performance. When the oxygen has been pressed through the felt it passes through the airstone towards the surface as small bubbles.

Which air pump do I require?

This depends on the aquarium, the purpose and the desired functions. sera offers membrane pumps in three performance steps: sera air 110 plus, sera air 275 R plus and sera air 550 R plus. Besides aerating the aquarium they can fulfill other tasks as well and supply aquarium devices such as the sera internal filters L or the sera gravel cleaner with air. Furthermore, they are suited for use with the sera automatic feeder for reducing moisture in the food, or for aerating the Artemia or phytoplankton breeding setup.

This overview shows which air pump is best suited for which purpose:

Decision criterionApplication fieldAir pump type
Aquarium sizeSmall tanks up to 100 l (26 US gal.)110 plus
Medium tanks up to 300 l (79 US gal.)275 R plus
Big tanks above 300 l (79 US gal.)550 R plus
Pond (only with weather protection for the air pump)550 R plus
Adjustability desired275 R plus or 550 R plus
Higher air pressure desire275 R plus or 550 R plus
Usage with devicesWith an automatic feeder for reducing food moisture (e.g. sera feed A plus )110 plus
Gravel cleaner (e.g. sera gravel cleaner )275 R plus
Breeding Artemia (e.g. sera Artemia-Mix )275 R plus
Breeding phytoplankton275 R plus
sera internal filter L 60 110 plus
sera internal filter L 150 and L 300 275 R plus
Hamburg mat filter275 R plus
Decoration (e.g. airstone )110 plus, 275 R plus or 550 R plus
Marine protein skimmers with airstone(s)275 R plus or 550 R plus
Ozonizer275 R plus

What characterizes the sera air pumps?

1. Pump performance

All three models transport the air with at least 100 –140 mbar, which equals as 1.0 – 1.4 m (3.3 - 4.6 ft.) water column. This means that, for instance, a connected airstone still bubbles normally at 1.0 – 1.4 m (3.3 - 4.6 ft.) water depth. The pressure can be increased to as much as 160 – 170 mbar by combining air hoses. The air 275 R plus and air 550 R plus models include a particularly easy electronic adjustment that allows adjusting the air requirement with a rotating knob. Power consumption is very low at 3, 4 and 8 W.

2. Operation noise

The sera air pumps are very quiet. Advice: You will receive the best results when hanging up  the air pumps – when doing so, no vibration is being transmitted to a cupboard etc.

3. Included accessories

In addition to the air pump, sera provides non-return valves for all models, which prevent water being drawn back into the air pumps. The air 275 R plus and air 550 R plus models include Y-pieces that allow combining several outlets into one air hose for increasing the volume along with simultaneous pressure increase. Particularly flexible air hoses with airstones and flow regulators are available separately as sera air sets S, M and L, suitable for the sera air 110 plus, 275 R plus and 550 R plus.

4. Replacing spare parts

The heart of the air pump, the membrane block, can be replaced completely. The filter felt collecting atmospheric dust can be replaced just as easily by the drawer construction.

You will find the technical data for our three membrane pumps here:

sera air 110 plus sera air 275 R plus sera air 550 R plus
l/h (US gal./h)
[equivalent to approx. l/min
(US gal./ min)]:
min. 110 (29)
[approx. 1.8 l/min
(0.5 US gal./min)]
min. 275 (73)
[approx. 4.5 l/min
(1.2 US gal./min)]
min. 550 (145)
[9.2 l/min
(2.4 US gal./min)]
Watts: 3 4 8
Produced pressure: ≥0.010 mPa (≥100 mbar) ≥0.014 mPa (≥140 mbar) ≥0.014 mPa (≥140 mbar)
Connectors: 1 2 4
Spare membrane(s)
(item No. per complete
replacement kit)
06730 06732 06732 (2 pcs.)
Air filter (item No.) 08819 08819 08819
Recommended accessory
(item No.)
sera air set S
sera air set M
sera air set pond L
Retailer search