The Bacteria house is made of ceramic that has been heat treated at 1300 degrees for 60hrs. This tremendous amount of heat causes the ceramic to break its internal bonds thereby creating an extremely porous structure that has a much greater surface to allow very large bacteria populations to colonise.
Due to the large quantities of tiny holes, mechanical filtration is also achieved. Large organic solids and decaying matter are degraded at a far greater speed than conventional media, and maintain the optimum ecological balance of aquarium.
Bacteria house is not made of calcium and as such will not erode and thus does not need maintaining, the bacteria house contains minerals and trace elements which is beneficial to aquarium life.