I would also recommend using and electric pump to aerate the pond. Much cheaper and more effective. Read posts on aeration. Bill Cody has great connections here. You can run air tube from the house for very cheap.

I agree about mosquitos. nothing will ruin a swimming hole faster. Minnows are way better. Gambusia "mosquito fish" have done well for me.

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery."
Winston Churchill