Koi Pond Aerator 101

If this is your first time to setting up an outdoor pond, then the most important thing you need to know about is proper aeration in the pond. This is particularly true if you are setting up your own koi pond as the koi, the plants, and even the bacteria will need a steady supply of oxygen. So how do you set up your koi pond aerator? Here are some tips that you should keep in mind.

  1. Location. The first thing you need to know about is the placement of your koi pond aerator. For the best results place your aerator within the bio filter system. If this is not possible, put the oxygen pump, as close as possible where bacteria will not commonly be found. Another option would be to install the bio filter within a water fall feature, if you have one within your Koi Pond.
  2. Air volume. Depending on the stocking levels, the volume of air needed will vary. Generally, the air to water ratio that should be followed is in the chart below:
  • At least 40 liters of air for every 1000 gallons of water
  • At least 80 liters of air for every 2000 gallons of water
  • At least 120 liters of air for every 3000 gallons of water
  • At least 160 liters of air for every 4000 gallons of water

How aeration works

As you can see, the ratio should be 40 liters of air for every additional 1000 gallons of water. This ratio will allow for the maintenance of safe and healthy levels of oxygen in your outdoor koi pond.

Additional guidelines must be kept in mind. This is because the volume of oxygen that the water can hold varies depending on temperature, salinity, and even atmospheric pressure. The important reminders are the following:

  • Less oxygen is held in the water as temperature of the water increases.
  • If you have a lot of koi fish, or if you have aquatic plants in the pond, the amount of oxygen in the water will decrease. This is because the more living things there are in the water, the more oxygen will be consumed.
  • Not only does oxygen retention decrease as water gets warmer, the respiration rate of fish increases. To make up for the oxygen deficiency, more oxygen should be supplied.
  • Too much food given to koi fish will only lead to decay, which uses up the oxygen in the water. The same goes for a large number of aquatic plants in the pond.


Caution must be observed when installing the aerator. Remember that the air pump itself should never be installed below water level unless a check valve is installed. Not only will installing a pump below water level be problematic should power supply be interrupted, it also increases the risk of electrocution.

Air pumps often come with a step-by-step guide in installation and you should follow the instructions. If you can, ask someone from the shop where you purchases the pump to install it for you.

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