Pond Boss Forums AERATION Systems questions Aereation design, advise needed

Welcome to the forum. You need a pump that will provide enough volume and air pressure. Air pressure needed to overcome the back pressure is 0.5 psi for every foot of water depth. So, for your 40 foot depth, you will need a pump that can produce air at 20 psi.

As for how much air, that is a bit more complicated. Basically you need enough diffusers (I like rubber membrane diffusers) that will move the entire water volume in the pond to the surface at least once per day for the length of time you are planning on running the system.

Here is a chart from Vertex on their diffuser water movement rates. Not all diffusers are the same, so diffusers made by another company might not move the same amount of water.