250$ each for $750 total? Is it in a flyway? On big front days do you see flight ducks using it?
Around here big farm ponds are a dime a dozen. The difference between say 750$ a year and 7500$ a year is location and, to a lesser extent, the consistency of water levels. If you all you shoot are local ducks the place will get shot out pretty quickly. When you drive in and jump all the ducks off of it, you're seeing most of what you will be hunting. If you are located near a big migratory path you will have trading ducks coming along all the time. That type of place generally is much harder to shoot out because of the larger population of target ducks. It's obviously harder to educate them all.
If it's an irrigation lake, or lake you can reliably lower the level to it would be worth me because you can manage the level to get smartweed and wild millet growing around the edges when you draw it down.