The air pump consists of a bellow made by Goodyear and Firestone.
The bellows pump produces a higher volume of air than a diaphragm pump
yet it has a lower pressure output. For aeration at 12 - 15 feet
depth, volume is the most important factor effecting the heath of the
pond.
The Diffuser:
The stone diffuser is critical to aerating your pond. The
smaller air bubbles make it easier for the oxygen to be diffused into
the water. The diffuser should be placed on the bottom of the
pond at or near the deepest point; preferably 10 -15 feet down.
It is also important to place the diffuser inside a 5 gallon pail to
keep it from getting clogged with the muck on the bottom. Tie a rope
to the pail and the airline for easy retrieval.
If your windmill is turning, with no unusual sounds coming from the pump
(such as a grinding or knocking noise) and there are no excessive vibrations in
the windmill, yet there are no bubbles coming from the airstone; or the airstone
only bubbles at 6 feet deep or shallower, you may have a failed one-way valve
rubber washer. This is not a big problem, just call and order some
replacement washers and follow these INSTRUCTIONS
on how to repair the One-Way Valves.
Windmills, Fountains, Aerators, Pumps, Parts, and Pond Cleaning
Bacteria
One windmill will aerate up to 2 acres of pond. 
