Tom, The windmill was originally for keeping a cattle stock tank full but will not keep up with a 1+ acre pond not to mention that it doesn't always blow in Kansas (no wind...no water). I was thinking about removing the windmill and putting down a higher volume pump in the same hole. Where would a guy start looking for a lab that could test the water and determine if it was okay for fish. If I were to fill the pond right now, I'm guessing that I would be doubling the amount of water with well water. Thanks for the posts.