Now idea if the set up will woork exiting to see iff anybody else have thoughts on this.
Here is a link pdf on page 13 there are some diferente drawings off differente hypolimnetic aerators
http://www.env.gov.bc.ca/wat/wq/reference/aerationapd22.pdf
I know the principal woork a friend off mine did service as a engenier soldier with NATO in former Joguslavia they buildt aerators like this in wery shalow (3-5m) bow's to be used as drinking water suplies for small wilages.
So if you have the skils to jump at it it would be great if you document the build.

Can you keep track on temp. and DO ?
And if so read any changes with your set up?

I would consider getting the trout out, or keep close atention to them anyhow.

PAUL