The cainster filter is a very popular alternative to the sump. it
draws water from the aquarium, forces it through its internal compartments
and then out through a spray bar.
The whole system is under pressure created via the motor head attached
to the top of the canister. It is the propellor which drives the system.
Canisters can come in many shapes and sizes, however they all have
a few things in common.
Internal Comparments:
This is the area where bacteria live. It is made up of 2 or more
areas (3 are shown in the diagram). The bottom layer (where teh water
enters the comparments) has a large filter sponge to remove larger
pieces of detritus (some contain special ceramic tubes here to evenly
distribute the flow of water)
