Air lifts pros and cons...

Let's start off with the Pros...

1. Very low power usage. Typically a 120 l/min air pump consumes 100W of power and can drive around 15kl/hr of water through an airlift...

2. Oxygen saturation of course!

3. The airlift is very simple. There is little to go wrong and there are no moving parts other than in your airpump. They are extremely low maintenance and robust.

4. They can be configured to turnover your pond volume as often as you like.

5. An airpump can be easily hooked up to a battery backup system that needs only be a fraction of the size of the equivalent water pump system and the backup system will last many times longer.

6. Running costs are dramatically lower...

7. Low pressure filters offer other benefits (no gas super saturation, easier cleaning, lower maintenance, easy to get to parts etc etc)

And onto the Cons...

1. Slightly higher initial capital costs. You will need a few air pumps, and slightly more large diameter piping than in a normal pond.

2. If you want to run the pond seamlessly on a standby battery system you will need an inverter UPS type backup which can cost a little money.

3. Because the water flow is low pressure with only a few mm of water head providing the water movement in the pond, there is some concern that perhaps your Koi will not receive the kind of exercise that they would receive under a pump driven water return system. Again careful design can also overcome this. A backup water pump can also be used on a timer switch to provide your Koi with the body building exercise that they may require. The Happy Koi jury is out on this one if the truth be told though...

4. Pond levels need to be maintained with a reasonable accuracy. A difference of 5cm should not be enough to break the system though.

And that's about it.

Airlifts. Consider them on your next Koi pond! With a bit of planning they can be easily implemented and they will save you mega money over the years...