The prerequisite of maintaining a healthy aquarium is to have a good filtration system. Aquarium filter removes contaminants and purify water. There are three basic aquarium filtration systems:

            a. Biological filtration

            b. Chemical filtration

            c. Mechanical filtration

Biological filtration is the process of breaking down ammonia and nitrite to convert them into nitrate that is much less toxic. For this conversion process there is necessity of oxygen rich water and a suitable surface such as rocks or media in the filter where bacteria can attach them. In small aquarium with small group of fish, only biological filter can maintain a healthy water condition.

Chemical filtration is the process of removing wastes from the water by using various chemical additives. Activated carbon is the most used method of chemical filtration. Use of chemical media removes chlorine, ammonia and phosphate from the water. However, chemical media should be replaced after certain period.

Physical barriers are used in mechanical filtration process. Those physical barriers such as sponges, filter pads etc remove solid wastes from the water. Mechanical filtration creates blockade for fish waste, uneaten food and other debris so that these cannot get chance to decompose in the water.  It is essential to change filter media or clean them regularly for the effectiveness of mechanical filtration.

 Now, lets talk about more specific filter types available for aquarium maintenance.

Internal Box Filter: This type of filter is usually placed inside the aquarium. Internal box filter can be attached with the glass very easily. This filter works fine for the small tanks like shrimps tanks or breeding tanks.

Canister Filter: In canister filter, water gets in through a pipe from the bottom and passes through the filter material. Afterwards, water gets back to the aquarium by a return channel. A pump is installed at the top of the canister and water gets processed by the circulation through the filter.  

Trickle Filter: Trickle filter can be placed both on the top and bottom of the aquarium. If filter is placed on top, the process of filtration takes place by pumping water over the perforated trays. When water passes through the trays, it doesn’t submerge the filter media but makes the media wet. Thus, chances of growing bacteria increases which aids in the process of biological filtration.

Installing a trickle filter at the bottom of an aquarium can greatly improve filtration efficiency and maintain water quality, but it necessitates meticulous planning, proper installation, and continuous maintenance to ensure optimal performance and avoid potential problems.

Power filters are called hang on back filter. This type of filter is commonly used by aquarists. Power filter offers very good mechanical, chemical and biological filtration. Power filters are very easy to install. Sponge pad is used to perform mechanical filtration. Chemical filtration can be obtained by passing water through activated carbon insert. Biological filtration can be obtained by the beneficial bacteria which grow inside the filter media.  

Sponge filter is attached over a tube from a power head. When water is forced to pass through the tube, there takes place a filtration in the sponge. Water debris which get attached with sponge allow bacteria to grow and thus establishes biological filtration.