The trickle filter is one of the oldest ways to treat water biologically. In addition to filtration, oxygen is also introduced into the water, which is why this system is very suitable for aquariums without skimmers. A packing material is used, which on the one hand provides a large surface area for bacteria and on the other hand does not clog too quickly. A coarse pre-filtration is advantageous to extend the maintenance interval considerably.
The water flows from top to bottom over the packing. The bacteria living on them break down (carbon decomposition) or convert (nitrification) water substances. At the same time, the air in the filter enriches the water with oxygen and removes the excessive carbon dioxide. Forced aeration with air increases the gas exchange.
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