I would not pull water from below the thermocline with a small pump. Do you know where your thermocline is? It's probably close to the 4 - 5 foot depth (hopefully deeper). Doing so would be pumping bad (read toxic) waters up into the water column that the fishies live in. Raise your suction hose up to be in a foot or two of water to avoid this.
What horsepower is the pump motor? It doesn't really matter as all residential pool pumps, even the largest residential pool pumps, will be too small for a 3/4 pond to act as an aerator. It could make for a good fountain pump, but that's mostly for aesthetics and does little for aeration unless you have many of them.
The best you can hope for is to spray the water into the air in as large of a fan as you can get. This maximizes oxygen absorption and surface agitation, but maximizes evaporation too. I think you are taking a knife to a gun fight. Don't mind my frankness...I'm just trying to help.
