I just intalled a 1/4 hp rotary vane compressor and two air stones in my 1/3 acre pond. I have a fake boulder that my wife got at a garage sale for $30 which is significantly big enough to cover the compressor. The question I have is how much air flow due they need? The boulder has no holes in it, it would be easy enough to install them though. But I don't like putting holes in it to introduce rain etc... I thought about using 2" PVC and supply an inlet and outlet air supply thru the bottom and come out on the outside of the boulder. That way I could eliminate rain getting into the system without having to drill holes. Does this sound like a reasonable idea?

Its not how well you do something,
Its how well you look doing it!