This is a biological and mechanical filter, in the first month the water will be cleaned mechanically, later, when the microorganisms multiply, it will work biologically as well.

0:00 plan 0:29 biofilter gravel 1:07 biofilter base 1:35 barrel drilling 2:25 fitting the connections 5:02 connect inside the barrel 6:20 water flow 7:14 biofilter material 7:44 biofilter material installation 1 10:45 how to clean sand 11:58 biofilter material installation 2 13:46 water into the biofilter 14:39 bio filter leaking 15:00 lowering the pressure in the system 15:11 sealing the cover 15:43 seal test again 16:12 how to clean water 17:13 external filter 18:51 explanation of the biofilter