Whilst most airation mechanisms are based on mechanical aggitation like splashers.... with such a depth, I wonder if it is preferable to consider air-stones at depth. This will give 25ft of absorption, and will stir the water column..
The drawback will be the significant pressure (1atm 15psi) needed to get the air down there..
But as it rise, expansion will improve the effects..
So... where do you buy a good airpump (compressor), running say 24v, that will run from solar..
Good O2 levels, would likely promote many other organisms to develop, and thus create a sustaining micro-system... so thinking about what trout eat and promoting that side could be a win/win..
I hope the noise of the bubbling, would be no issue..
But you would need to devise a platform/shroud to prevent sucking the mud from the bottom, turning the dam to mud.... eg. A sunken IBC with the top cut out.
Retired Engineer and keen PV experimenter - Always ready to learn and share.
2 x CMS2000 (fan cooled) GCI and SE 170W panels
1.7kW First Solar/Outback Island circuit - Peak Replacement Power
Governments won't save the world
They will just TAX it