How much air to put into a Koi pond

A lot! You simply cannot over do it

Nigel Caddock NI

How much air is enough?

Aeration is about control. By deploying air pumps to make sure that DO levels are sufficient, you take control of one of the primary requirements of your Koi system, as a basic principle we believe this to be a sound principle. As far as we are aware no one has previously put numbers to the requirement of air. In good NI tradition we figured its time someone did - so we have!

The numbers in our unique table which incidentally was created for and first appeared in Koi 2 Kichi necessarily are indicative as they need to accommodate an almost infinite number of variables: stocking rate, feeding rate, filter size, filter efficiency, maintenance, etc, etc etc.

The truth is its virtually impossible to fulfill all these in a model that could accommodate all the variables, so our numbers necessarily make some assumptions and judgements and to a degree rely on experience.

While we fully recognise this empirical approach is not perfect by any means, by the same token it also deploys our combined experiences to offer what we believe to be a sensible working guide. In general terms, 40lpm per 1000gallons is a good rule of thumb.

We adjusted the numbers simply because of some general principles, for example ponds up to 9000 tend to be stocked heavier than ponds of say 20,000 gallons. In addition bigger ponds tend to have bigger surface areas which generally offer better DO exchange opportunities than smaller ponds. These comments are offered to provide only a context for the numbers not to justify or qualify them, and we would again reiterate their entirely indicative nature.

Pond Gallonage	1000	2000	3000	4000	5000	6000	7000	8000	9000	10 000
Pond volume in litres	4500	9000	13 500	18 000	22 500	27 000	31 500	36 000	40 500	45 000
Litres of air/min required to maintain DO at Koi Safe Levels*	40	80	120	160	200	240	280	320	360	400

* These numbers are of course entirely indicative and advisory only. They are also based on 30 years experience and are an excellent rule of thumb. All the above are in imperial gallons.

William's note: These figures are high indeed! It boils down to shere experience and why I continually harp on our need to add more air to our ponds in South Africa. More air means better fish growth for one thing and more air means less likelihood of large fish suffocation (the large fish are the first to die in oxygen poor environments).