Vince,
In a two year old pond you should have no problem (key word should). Older ponds have more decay, so they usually need little more oxygen. Deeper ponds do really well in the winter time because they have a bigger air reservoir in them, but be very careful about deeper ponds stratifying on you in the summer.
Have you looked at the diffuser/ bubbler aeration systems? You hardly see it working. Even better it gives you air in the winter, by keeping the ice off, and keeps your pond from stratifying in the summer. At my hatchery, I just dig a hole in the ice and plop the diffuser in. When I come back, 24hrs later, there is a hole dug out about 15ft in diameter.
You also can look at directional aeration systems, (simply a nozzeless fountain that sits parallel with the bottom.) These work well if you have a cove. If you have an oval pond you can put two of them down and they will give you a natural current. (Theses are great for species that like a moving water.)
If you need some help finding these systems get in contact with me via email.(hit rate member icon) I have done my homework, and I can show you some quality aeration systems at great price.
