My kitchen sink worked fine before. Recently, I had a new, deeper sink installed (10" deep; also bigger in length and width), with a new disposal, and got rid of the air gap. Now, when I pour a pot of water in the sink, it drains down very slowly. If I turn on the disposal, the water goes right down. Will an air gap help drainage by allowing the air in the disposal to escape to somewhere? Is the bigger/deeper sink somehow causing this problem?