Josh
I agree with Dave - go Honda. Northern Tool has them on sale currently for 300-400 bucks and they do 14k GPH. For your pond thats almost an inch and hour. I know Treeplanter is thinking of buying one but wanted to cost share it. Might be worth contacting him. [Name is Matt and tell him I sent you].
Gotcha. How do I contact Treeplanter? Here at the forum?