We are new to pool ownership, and having a couple issues. We recently bought a house with a large inground pool 20x40. It was left uncovered for probably 2 years. We are trying to open the pool and have run into some complications. We have a Hayward super pump, and also a Hayward sand filter. We cannot seem to get the pump to prime, after adding water to the pump basket, it just runs and doesn't prime. I have replaced the O ring on the pump lid, but still doesn't prime. I am not sure if we have a clog in the skimmer return lines, a clog in the pump impeller, a filter issue or a nice combination of everything. We have also noticed that the filter leaks under the edge of the multiport valve, and water leaks out of the backwash port. Any help or suggestions would be of great help! TIA!