When placing filter cotton, special attention should be paid to the problem of several layers. For the general fish tank, that is to say, the number of fish is not too much, the use of 2-3 layers of filter cotton can be. Of course, if the number of fish in the tank is very large and the fish are very dense, then the pollution of water quality will be relatively faster, at this time, more filter cotton is needed. But generally speaking, the number can not be too large, otherwise it will be harmful, resulting in waste, will also block the flow of water.
Under normal circumstances, the upper layer of filter cotton can use physical filter cotton, which is used to filter large impurities, such as food residues, feces and so on. Therefore, they are easy to get dirty, especially when the water quality is poor and there are many impurities. Therefore, physical filter cotton can be placed 1-2 layers according to the specific situation, it is recommended to place two layers, because some physical filter cotton thickness is not enough, and sometimes the quality may be poor. The lower layer can be placed with large gaps of biochemical cotton, which is helpful for the beneficial bacteria system in the fish tank. Because of the barrier of the upper layer of physical filter cotton, biochemical cotton is not easy to get dirty.
The above has been introduced, generally speaking, when placing filter cotton 2-3 layers are more appropriate. If only one layer is placed, it is generally a physical filter layer. If the number of fish is large or the filter cotton is thin, the filtering effect may be poor and the water quality may deteriorate. As far as possible, physical filter cotton and biochemical cotton are placed in a layer, which is helpful to the health and growth of fish.
