Mechanical fitration is the term used to describe the removal of particulate waste from the aquarium. This includes uneaten food, dead plant matter, fish waste and surfectants such as dust. In your Bio Filter, primarily the coarse and medium foams carry out the mechanical filtration

With more basic, less effective filters these foams would also be providing biological and possibly chemical filtration. This would prevent you from being able to fully clean them when they become clogged, as to do so would remove essential bacteria from the foam

However, as the Bio Filter has separate biological and chemical filtration areas, this is not a problem. When the foams become blocked, simply clean them thoroughly in warm water

Chemical filtration takes place in the bottom foam of your Bio Filter. This foam is impregnated with carbon.

The carbon will help remove odours, toxic heavy metals and chlorine, water discolouration and unwanted treatments. The carbon foam has a finite life span and should be replaced every 8 weeks

The carbon foam must also be removed if treatments are in use, as if present it will remove the treatments, rendering them ineffective. Once the treatments have run their course the carbon foam can be placed back into the filter

0833 Coarse Foam : 10ppi : Pre-filter foam to trap large waste particles

0834 Medium Foam : 15ppi : Traps medium and fine waste particles

0835 Carbon Foam : 15ppi : Chemical filtration

The above three foams are all fitted as standard

0836 Fine Foam : 20ppi : Optional Extra : for "polishing" the aquarium water once large waste has been removed

If used, it would replace the Medium foam