My Geo discharges at the edge of my pond. I don't think that a geo discharging at the bottem of the pond will keep the ice from forming on top of the pond. It might cause a problem because you would be pushing the water out under the pressure of the water. I could be wrong on this. Where my geo discharges at the side of my pond leaves only a very small hole open free of ice. Lets see what others may think.