I have a 16x32 inground pool that is 8 ft deep. I have the liner out because of problems with ground water. The deep end of the pool has a rock bed which tells me that ground water has always been a problem. I now need to pump water out of the rock bed so I can repair the floor and walls. I have the pipes to do this but I need to know what kind of pump I need. The pump will need to sit on the edge of the pool and suck the water up to it. Any help will be appreciated