What is the filter material of the fish tank and what is the order of placement?

The first stage: put fiber cotton in the physical filtration stage (note: socks can be put on the outlet of the water outlet to filter out suspended substances, which is convenient for cleaning);

The second stage: chemical adsorption filter materials such as activated carbon, ammonia-absorbing stone, zeolite and clear water resin are placed in the chemical filtration stage (note that the adsorption effect of such filter materials is generally only three months and must be replaced);

The third stage: the first stage of biological filtration is to place biochemical cotton (note: it is best to choose the one with suitable pore size, high strength, high elasticity and high filtration speed);

The fourth stage: putting biochemical balls in the second stage of biological filtration (note: the capacity of this stage is greater than the number of biochemical balls as much as possible);

The fifth stage: the third stage of biological filtration is to place porcelain rings (note: the higher the water absorption of porcelain rings, the better; The higher the surface roughness, the better);

The sixth stage: in the fourth stage, yellow coal or aquatic sand is put in by biological filtration;

The seventh stage: put the fiber cotton into the water balance box, and the submersible pump will transport the filtered water back to the fish tank. (Note: If it is upper filtration, you can cancel this stage and let the water naturally flow back to the fish tank. )