### Aquarium and accessories (I) | Pet care.

When choosing an aquarium first thing that has to take into account is the best thing to do is to buy it as large as possible. In addition, simple (and perhaps outdated) rectangular aquariums are infinitely better than the "design" with rounded, irregular forms, etc., which only take into account the aesthetic (?) and forget about practical issues.
A large Aquarium offers many advantages:

1. It is easier to maintain stable water quality, and therefore, it reduces routine maintenance.
2. The temperature is kept constant. In the case of a power outage, the water is cooled as quickly as in a small Aquarium. Heating costs are proportionally lower than a small Aquarium.
3. Its interior space allows you to create a more attractive decor and it can easily camouflage devices such as filter internal, heater, etc.
4. It can hold more fish.
5. Their decorative effect is more striking.
All these aspects relate to the typical decorative home Aquarium. Breeders employ smaller aquariums for the playback of your guppies, as well as for the quarantine and treating illness. As a general rule, more expensive aquariums tend to also have a longer shelf life and are built with better quality than the cheap glasses. For the amateur, which starts with the guppies is usually enough with a 60 to 120 litre capacity Aquarium. But if you take a look at it, nothing prevents done with one of larger capacity. However, must not forget that water is heavy and that and you need to support able to perfectly withstand the weight of the filled Aquarium.
To calculate the volume and the weight of any Aquarium can be used the following formula: volume = length x width x height
If the lengths are expressed in Decimeters, the volume is obtained in liters.
Suppose that the Aquarium measures 100 cm x 40 cm x 50 cm.
Volume = 10 dm x 4 dm x 5 dm = 200 litres.
Therefore, the water contained in it will weigh about 200kg, to which must be added the weight of the Aquarium itself, most of the gravel, rocks, appliances, etc., so the final weight can reach increase by 25-30% with respect to the water. This aquarium 200 liters would weigh, full, about 250-260 kilos. And this is the weight that must be in choosing the proper support.
Choosing Aquarium it is best to choose one that already incorporates a lid with integrated lighting display.

### Population of the Aquarium

The maximum population that is capable of supporting an aquarium is determined by several factors. The main ones are these:
1. The water temperature. More cold is, more oxygen may contain within its ranks.
2. Your level of cleanliness. Dirty water contains less oxygen than clean it.
3. The size of the fish. How much greater, they will consume more oxygen.
4. The activity of the fish. How much more assets are, they will need more oxygen. (The temperature also influences the degree of activity).
5. The number of plants. Natural plants consume oxygen during the night, but do not constitute a determining factor as they emerge during daylight hours.
6. The chemical composition of the water. This affects the amount of oxygen that can dissolve both the activity and the breathing rate of the fish.
7. Contact surface of the water with air. Atmospheric oxygen is dissolved in water through its contact surface.
For practical purposes, we can consider that the depth of the Aquarium is not a limiting factor. It provides more space for fish and plants, and affects the amount of light that can reach the lower levels of the Aquarium. Very high aquariums and devices that produce a correct circulation of the water could cause a stratification of temperatures.
Of course, if it is necessary to strictly take into account all these factors we could make us a tremendous mess when calculating the population of the Aquarium. Luckily, the aquarist have established a rule of thumb that works wonderfully in most cases. In a normal and properly maintained Aquarium, fish can be because of 2, 5cm of fish (excluding tail) per 4 liters of water, or 2. 5 cm of fish per 80cm2 surface.
For example, a 100x40x50cm Aquarium has a surface of 4000 cm2, so it may contain 125 cm fish. If we assume that the average length of the guppies is 4 cm (averaging males and females), we see that we could place a 31 copies in our aquarium. If copies are placed juveniles can increase the number, but it will move them to other aquariums they will grow to avoid Aquarium sins of overcrowding.
These population levels may seem fairly low, and it is worthwhile that let's them something more. This rule of thumb assumes that the Aquarium does not have any technical auxiliary material and that it remains in a biological balance (which is almost impossible to happen) in which only partial water changes are performed. In practice people can dramatically increase if increases the concentration of oxygen from the water and debris and droppings are removed.
This can be achieved through aeration and water filtration, but must be taken into account that if devices stopped working (by fault or by cutting of electricity), Aquarium conditions would deteriorate quickly and the smaller the Aquarium, before serious problems arise.
The prudent aquarists never risk overpopulate aquariums by the fact of having a few devices that theoretically allow them to do so. Ideally, keep on a term, i.e., include some fish more but without reaching the ends that could create situations of stress and violence, as well as it would force the filter capacity.

### Aeration

The function of the aerator consists of agitate the surface of the water based make ascending air bubbles from one or more diffusers connected to a small air pump. The result is an Upflow bubbles that constantly break the surface of the water. This movement creates small waves that are those that increase the surface of contact with the air and allow a greater diffusion of oxygen.
Seen this, we realise that there is a widespread mistake about these bubbles. The water does not absorb nothing (or almost nothing) the air contained in those bubbles, and only account the effect generated in the surface. When ascending, bubbles create a side effect, as they carry water behind them and generate a stream of water up. This causes gases in solution from rising to the surface and be removed, creating a water circulation which will also help the Aquarium heater.
The size of bubbles has a certain importance. If they are too big they rise very quickly and they can not drag water behind them, and if they are too small they do not carry sufficient air to agitate the surface and do not generate a correct circulation of the water. To obtain the correct balance, it can be necessary to experiment a little.
A proper ventilation may allow to double the number of aquarium fish, but can also be used to create a decorative effect. Favourite broadcasters tend to be porous ceramic. They can be small or large, to create one or more streams of bubbles. You can blend discreetly in the back of the Aquarium, or used as an ornament.
There are two basic types of air pumps: membrane or piston. The membrane are the most economic and popular. Pump must be placed in a place higher than the Aquarium to avoid causing an effect of trap (with the consequent flood) in the event of a fault or power failure. It can be hung or placed on a non-slip surface, otherwise, their vibrations would make a certain noise and the device would have a tendency to move. There are bombs of many sizes, depending on the flow of water that are able to provide. On some models is controlled through a button, and others flow with a clamp that presses the air tubing.