Frequently Asked Questions

Q. How will the Windmill aerator improve my pond?

Aeration is the most important thing you can do to improve pond/Dam water quality. Oxygen is a main element of water, the more air in the water the better the Eco System becomes.

Once the water quality is improved it will begin to combat algae and aquatic weeds naturally – some folks call this a balanced pond. The aeration will take the ammonia, nitrate and hydrogen sulphide gases out of the pond, removing the food source from unwanted algae.

Q. Where are the NZ Stirrers made?

In Silverdale, Auckland. Every Windmill is hand made.

Q. Can this Windmill pump water?

Yes, they sure can. Every client has a different situation they need water pumped from or too and that’s why we ask you a few questions to find out what your particular needs are. In short, we can draw water from your Dam/Pond and push that water over a kilometre* away and uphill, 500m* to your holding tank.
This will depend on the Windmill size and pump configuration. The great thing with our pumps is we custom build each pump to meet the client’s needs.
Approximate Volume of water pumped based on 8 to 10 knots of continuous wind (24hrs).

Daily: 52,000 litres
Monthly: 1,580,000 litres
Yearly: 18,900,000 litres

Based on 22mm pipe @0.6 litres per sec – pending height/distance
100% Environmentally Free Energy

Q. How far can the Windmill be from the pond?

For pumping water – as close as possible.
Aeration Windmills can be over a Kilometre away sitting in the most favourable location to catch the wind.

Q. Do I need a freeze control unit ?

No. Unlike diaphragm compressors that make short 1/2-inch rapid strokes causing condensation that will freeze below 32 degrees, a NZ Stirrer bellows huge 1 & 3/4 inch stroke will not produce condensation.

Q. How many air stone diffusers will I need?

This will depend on the overall size and depth of your pond/Dam and will be between 1 and 4 air stones. The deeper your pond the less air stones are needed. Reason being when the air is released from a depth it goes into a cone shape spreading out the air bubbles wider as it heads to the surface creating a wider aeration.
Keep in mind by adding more air stones does not produce more volume of air, it only splits the amount of air from the compressor by the number of stones used. Our largest Double Bellow Aeration System is the 12CFM.
Approximate Volumes of Air produced based on 8 to 10 knot of continuous wind (24hrs).

Daily: 500 cubic metres
Monthly: 15,200 cubic metres
Yearly: 184,000 cubic metres

Q. Will this Windmill make electricity?

No – sorry

Q. What is the size of the hub/wheel & tower?

NZ Stirrers offers 3 different sized Windmills. These all have a 3.0m Hub/Wheel Blade configuration that turns counter clockwise, made to look like the old fashion water pumping Windmills.

All are wide stance four-legged towers for more stability than the three-legged towers. Windmill Sizes: 8.0m – 10m – 12m

The Towers are made from either Galvanized Steel Angle unpainted or out of Cor-Ten Steel that will give a rusty, rustic finish/look that it has been there for the past 100 years.

Q. Does a bellow pump intermittently?

All diaphragm & bellows pump intermittently. Most diaphragms only take a 1/2-inch stroke or less so the pulsation is not noticeable. The NZ Stirrer bellows makes a huge 1 & 3/4 inch stroke so the 3 & 1/2 times more volume of air is more noticeable.
The intermittent pulsation not only provides more volume of air it also is much more efficient in circulating the water. The bellow is the most effective way to draw the bottom water to the diffuser, Rejuvenating it with fresh smelling air and with the aid of the intermittent pulsation it aerates & circulates  the entire pond from bottom to top.


Q. How deep should my air stone diffuser be placed?
The NZ Stirrer Double Bellow Compressor is capable of pumping to 6.0m deep. However, a study has determined that for best results the air stone diffuser should rest at about 1/4 of the pond’s depth – particularly if keeping fish.
The study found that during the summer the fish like to go to the bottom where the water is cooler, if the diffuser were at the very bottom it would bring the cooler water to the surface where it would be heated by the sun – causing the entire pond to warm too much.
In the winter it works just the opposite, the fish metabolism slows down and they go to the bottom for warmer temperature water, if the stone diffuser were at the very bottom it would bring the warm water from the bottom to the top and chill the water to almost freezing temperatures.
Keep in mind the bottom 1/4 will still get aerated but just at a slower rate so as not to disturb the natural temperature welcomed by happy fish.
Q. How many CM (cubic Metres of air per day)?
Cubic Metres of air introduced into a pond is far more important than pressure. It has been estimated that the NZ Stirrer Windmills can produce up to 12 CFM in strong winds. Our largest Double Bellow Aeration System is the 12CFM (Cubic Feet per Minute)
Approximate Volumes of Air produced on 8 to 10 knots of continuous wind (24hrs).

Daily: 500 cubic metres
Monthly: 15,200 cubic metres
Yearly: 184,000 cubic metres

Q. Will this windmill over speed?

No. NZ Stirrers has a built-in self-governing regulator in the design of the wheel. Even though the windmill uses three of the highest quality line shaft high speed grease able bearings rated for 2,000rpm, it is still designed to turn away from winds in excess of 72kph to prevent any over speeding.


Q. How do I anchor my NZ Stirrer windmill?
Your Windmill will be fixed securely by four 3m long (32mm) galvanized steel rods. They are hammered into the ground on the same angle as the Windmill Tower. They work great in heavy clay soils.
However, we do recommend that you secure the Windmill with a 200mm concrete base that exceeds outside of the Tower base by 400mm.
Don’t forget, I will personally erect your Windmill anywhere in New Zealand for peace of mind.


Q. What is the advantage to sinking hose over floating hose?
We use a floating hose from the Windmill Compressor to the water’s edge. From here we use sinking hose which is more expensive and can be used all the way to each air stone diffuser. Sinking hose is much easier to work with, but is more expensive. We recommend the sinking hose for faster and neater installations. All ponds are different so contact us for a custom quote.
Ideally, if you are about to construct a new pond, I will ask you to install 40mm PVC piping into the clay lining so we can thread the hosing through it having an upstand off the bottom of the pond for the air stone to sit on.


If your question is not covered on this page, please do give us a call or send us an email.