I'm confused. I thought you would want the diffuser very close to the bottom so that the anerobic bottom muck would be exposed and thus begin to degrade. I know I read that somewhere....lol
Our pond is heavy clay, I mean our township was well known for making clay bricks and field tiles.
This clay as it get super saturated with water turns into a jello that is about 10-16"s deep.
From the beginning of time with the aeration we have had a visibility of about 18"s max. The other day I pulled water from the pond and let sit in a bucket and fine clay settled out.
I am thinking of 24"s more than what we are at now and see if it makes a noticeable change.
Cheers Don.