How to aerate the aquarium water

Oxygen in the water comes mostly from the souranding air (gas diffusion process) and from the photosynthesis processes. Photosynthesis will occur only if there are plants in the aquarium and there is a source of the light. At night when there is no light plants will start absorbing oxygen from the water. The solubility of oxygen in the water depends on several parameters like:

If the dissolved oxygen in the water is in equilibrium with the oxygen present in the atmosphere then it means that water is one hundred percent saturated with oxygen. Also keep in mind that the air-water system always trying to get to balance of the oxygen content.

We say that there is the lack of oxygen if there is a difference between the concentration of the oxygen under the given conditions (at the same temperature and pressure), and the actual amount of oxygen in the water.

The water is supersaturated with oxygen when the concentration of dissolved oxygen in the water is greater than in the atmosphere (at the same temperature and pressure). This phenomenon is conducive to a rapid rise in temperature or sudden pressure drop and increased photosynthetic processes. It may cause a fish disease called gas or bubble disease - water saturation of 30% will kill all your fish in the aquarium.

The effects of insufficient amount of the oxygen in the aquarium are:

We use additional aeration in the aquarium when we observe that our fish are spending most of the time just below water level and we already eliminated other possible causes of this condition. Also if we have to many fish comparing to amount of plants in the aquarium.

Aeration of the aquarium is an artificial induced process, which is increasing aeration of the water  and to equal its concentration at all points of the aquarium. Additionally oxygen contributes to the remove unwanted gases from the water (for example, carbon monoxide) and is involved in the partial oxidation of the pollutants.

Water aeration efficiency is affected by:

In aquarium additional aeration is done by:

When selecting the aeration equipement we should pay attention to the following parameters: