I am in the process of having my inground pool's liner replaced and the guy doing it asked if he can plug the drain in the bottom of the deep end. He said that they often leak and are tough to repair. I am hesitant to let him because I am assuming that if it wasn't needed it wouldn't have been installed in the first place. If the drain is plugged the only feed to the pump would be the skimmer. The pool is approximately 40,000 gallons. Do I need to keep the drain?