jdmcalf, I too have rainbows and am looking at aeration. This is a new pond dug last fall, no vegetation yet and have just stocked 150 trout 5-7". Pond is 150ft x 50ft x about 12ft deep.
Bill Cody, yourself and others have helped me get started already but I am intrigued by your opinions on aeration specific to Trout. First, Bill had suggested that I MAY not even require aeration for the first couple of years due to low amounts of sludge and nutrient, (I am not feeding) and has explained the benefits of a diffusor style system.
I do intend on over-wintering at least some fish. Alberta winters are very extreme, with ice on by Oct/Nov and not off until mid to end of May. Ice thickness last winter on local lakes was 30" minimum. I realize the benefits of removing snow, but am undecided on aeration and after reading your posts I am more unsure. Any comments are welcome.