Signal13...First off, welcome to the forum. We are working late tonight so I think I will be the first to comment.
Questions first:
1.How deep is the pond?
2.How old is the pond?
3.What kind of land is around the pond, farm, pasture, subdivision, and does the watershead from this land end up in the pond?
4.Is it an unusual shape?
These all help to size a system. When an aeration system is sized, the goal is to turnover the entire volume of water so many times per day depending on the nutrient loading, hence the questions about the land around the pond.
Just from the limited information you gave, a single diffuser set up should be more than enough to properly aerate your pond.
As for the surface system. They are great emergency aerators or for ponds like trout ponds whereby the thermocline is to not be disturbed but in your case unless you want a fountain for esthetics and make the water look pretty as it is thrown up in the air it would just be overkill.
As for the stocking rates, I will leave that to the guys here that are more adept to stocking like Greg Grimes with Aquatic Environmental Services.
I'm sure others will chime in tomorrow morning as they do like I do and review the forum as I drink my first, second and third cup of coffee.
Again welcome and happy ponding.
