A good koi pond filter is divided into 2 parts, namely biological filtration which functions to organize aerobic bacteria (nitrification) which will break down the chemical components in fish waste or excrement. The second is the Mechanical filtration system, of course, this system is for physical waste before-mentioned as fish excrement, dry leaves, dead insects, etc. Most ponds generally have a bottom drain. This is used to make it easier to clean the dirt that falls to the bottom of the pool, for the location of the channel you can make in the deepest part of your pool. A pond that does not have a bottom drain will make sewage accumulate at the bottom of the pool, for that this type of pool must be absorbed or drained to remove the sedimented sewage. In a pond that has a bottom drain, a drain is usually placed in a holding tank or settling tank.

The water that flows from the lower drain is directly collected in the settling tank, where the sewage will be allowed to settle at the bottom while the air on the surface will flow to the pump. On the pipe from the tank to the pump, a filter such as a biofilter should also be installed. This is to regenerate water from waste or dirt that does not settle and ensure that the air is completely clean before returning to the pond. You also have to pay attention to the airflow from the lower drain in the pool according to the size of the pipe installed. The airflow that is too slow will not make the sediment impurities settle in the layer and be transported into the water tank.

To help you make the right bottom drain, you can choose a pipe with a size of 3 inches and use a suction pump with a capacity of 1500 gallons per hour. and if you use a 4-inch pipe that means you need a suction pump with a power of 2500 gallons per hour. And to make sure you choose a settling tank with the right size, you can match it with the bottom channel you made. The correct tank size is 10% of the bottom discharge capacity of the pond. That is, if you use a 4-inch pipe with a flow of 2500 gallons per hour, it means that the ideal volume size of the settling tank is 250 gallons.