HagenKB

Filtered aquarium requires an Airstone?

I have a power filter for filtration, do I still need an airstone in my aquarium?

I have a power filter for filtration, do I still need an airstone in my aquarium?
Depending on the filtration you are using and how it is placed, normally there is no problem with lack of oxygen in the aquarium. An air stone, for most uses is generally decorative. Although, the bubbles breaking on the surface do disturb the natural surface tension and promote surface agitation and an aerosol effect. This agitation encourages carbon dioxide release from the water and oxygen entry into the aquarium. When an airstone is installed, the bubbles, as they rise, do not appreciably add anything to the water at all. They are moving too fast and rise in too short a distance to pass any oxygen to the surrounding water or absorb any carbon dioxide. The contact time between bubble and water column is simply too short.

As long as the filter output does cause sufficient surface movement, in most ordinary cases no additional oxygenation is required. If the water surface is still, there may not be any good interchange going on. If the fish stay near the top of the tank and always appear to be gasping, then it may be a strong indication that something needs to be done to increase surface agitation. In the first attempt, move the output from the filter in such a way as to create more surface agitation from its exhaust. Adding a decorative airstone with an air pump that also agitates the surface as the bubbles break is another alternative, but as mentioned in most cases it is best looked at as a primarily decorative addition to the living picture.

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