Filtration can be considered as three major types
- mechanical - remove particles from the water to keep the water sparkling clear and to maximise the efficiency of subsequent biological or adsorptive filtration
- biological - ensure the breakdown of waste products in the aquarium by 'friendly' bacteria
- adsorptive/chemical - uses media that removes various substances from the water. It can also refer to a media that can acidify water by adding humic and tannic acids.