TG4,

Good questions. Other information would be required to make sure the right number and type of diffusers are used on your pond.

What is the depth? How far is your power source from the pond? Any unusual items like an island in the middle? Pasture land washing into the pond?

All of this will aid in making suggestions for you to make an informed choice.

Compressors, the newest and greatest is the WOBL piston compressors. They are not effected by deep depths are long runs of tubing and they generally have a 3-year life before a maintenance kit is required.