How deep your pond is usually determines how much $$$.
If you have a shallow pond, you can aerate it with a high volume/low pressure pump that costs alot less $$$. Also if your somewhat near the metro ATL area, I would contact lakework.com to help with your aeration system. Anyone can pump air...let me start over, Almost anyone can pump air to the bottom of a lake, but not too many people can properly place or grasp the concept of AERATING!
If your oxygen decline is related to your plankton bloom, your fish have plenty of oxygen during the day because they put off oxygen, but at night that will actually cause a reverse effect and suck the oxygen out of the lake.
