Aquarium water filtration methods

In natural environment water is able to regenerate itself. Water in the aquarium do not have that ability almost at all.

Aquarium water filtration methods.

Regular water exchanges

This method is effective if is done regularly. It requires water exchange to be done every two weeks by exchanging 25% of the water combined with the desludging substrate.

Mechanical filters

This filters stop on its surface greater part carried by the water. Filter material can be foam or wool gauze pads . This type of the filter  has an additional functionality - it put the water in motion and oxygenates it at the same time.

The main parameter of the mechanical filter is their efficiency which is the amount of filtered water per hour. The table displayed below shows the dependence of the filter efficiency required for the chosen tank size (values are approximate and depend on manufacturer):

Biological filter

Stops many different (including organic) contamination which is removed by the bacteria spread over the surface of the filter. The amount of oxygen flowing through the filter determines the degree of decomposition of organic compounds. Filter consists of two parts. The first (inlet) part is usually the same material as used for mechanical filters, the second part is fine gravel (bacterial flora develops here). The first layer of the filter should be cleaned frequently, the other layer of the filter (fine gravel) should not be cleaned to often. This second  layer should also not be cleaned all at once to protect bacteria. As the bacteria in the filter consume oxygen we need to give the water additional motion. The volume of the filtration material should be at least 1 litre per 100 litres of the aquarium water.

SUMP - external filter

What is a sump? Sump is an external filter which is usually located under the tank. It has several layers and filter compartments. You can have various elements to aerate the water. Usually it is made of smaller aquarium with additional glass partition to create the chambers. Each chamber is filled with different filter media to improve filtration. To increase the water aeration you should raise the pipe (which enters the sump) above the sump's water level.It will create a shower effect which by splashing against filter media aerates the water. Water flows throughout each chamber and than after getting to the last compartment it is pumped back to the main aquarium.You need to remember that water flow should always be continuous. There is a nice diagram displaying water flow in the sump.

Chemical filter

Chemocal filter is binding certain chemicals and releasing others. Below I will present most popular types of filters and what they are used for.

•  Filter with activated carbon called carbon filter - is the most common example of a chemical filter. It binds chlorine, methane, proteins, organic acids, colorants on its surface. It does not release water from ammonia and nitrite. It works really well if you need to remove medicines or chemicals used in the treatment of sick fish, etc. Most popular are activated carbon cartridges used in filters as one of the layers. It is ideal solution for spawning aquariums or to prepare water for fry. Durability of this filtration material is around 1 month and there is no possibility of its regeneration. You have to carefully use this type of filtration as it removes some of the elements required by plants.
• Peat filter stops the various chemical compounds and releases humic compounds (which lowers the water pH) and enrich the  water in tannins. In addition it purifies the water from the slurry. Requires continuous operation - downtime is not recommended. Peat fiber with low ph and no fertilizer is the best as it does not make water dirty. Before you use this filter in your aquarium you should start it outside the aquarium until water coming out of the filter will be clear. The bacteria in this filter should develop in approximately two weeks. It should be replaced periodically because it loses its properties.

What aquarium filters can be found on the market?

• external filters
• internal filters
• cascades
• filters using reversed osmosis RO
• UV filters
• under substrate filters