article: Aeration and space
It is said that the fish when they breathe using oxygen dissolved in water, so when designing an aquarium the main concern should be to provide the necessary amount of oxygen fish, making sure that the precious gas enters the water. Each fish requires a certain amount of space to swim and grow, but space is also important to define the various territories that individual fish demand and defend themselves. These two basic problems, that of oxygen and that of space, are easy to find a solution in the simple expedient of choosing a tank size and proportions correct. It 's important to understand in detail how gas exchange takes place and how much oxygen is needed. Oxygen enters the water from the only partly possible: the free surface of the water itself, and any other gas follows the same path. Why enter the water the more oxygen, the surface area of liquid should be as wide as possible. Between two tanks of equal volume you should always choose the one that presents, compared to water the greater the free surface in contact with air. In fact this surface in contact with air can easily absorb oxygen, but also allows the removal of carbon dioxide emitted by breathing in fish (and plants, which also breathe day and night). Carbon dioxide "out" of oxygen from water much more slowly, and for this reason the ventilation is very important. Contrary to popular belief, aeration (with its prominent column of rising air bubbles that dissolve immediately in water) does not increase the amount of oxygen dissolved in the aquarium. The oxygen is absorbed much more rapidly on the surface. The real purpose of ventilation is to create a "turbulence" on the surface, so as to facilitate the escape of carbon dioxide from the water. The ascending currents caused dall'aerazione mean that the water is continuously stirred; in this way in the aquarium tropical eliminate any pockets of cold water. The overall effect of ventilation is to increase the possible number of fish contained in the tank, although there should be based on this concept when, initially, we introduce the fish in the tank. Necessary to calculate the space for the development of the fish and to make sure that, if for some reason the aeration should fail, the fish does not have a sudden loss of up to remain asphyxiated. Another factor that contributes to oxygenate the aquarium is the presence of the plants. During the period of lighting, plants perform photosynthesis, that is, using the carbon dioxide and produce oxygen, to fabricate the substances referred to live. But all plants breathe normally (that is illuminated in the dark) by absorbing oxygen and giving off carbon dioxide. And 'therefore absolutely vital the relationship between plants and animals to create a microenvironment in perfect balance.