I lose my pump prime after turning pump off for a while

[christina1]

I have an inground pool hooked up to a hayward super pump and DE filter. Whenever I shut the pump off for the night and go to turn on next day I have to re-prime the pump. The pressure while the pump is running is ok. I replaced the inner seal in the pump and I am not losing any water. I do not think I have a leak in the underground pipe but I do notice that the hose that goes from the filter to the heater is slightly leaking could this be my air leak. Thanks