We have a new inground pool, less than 36 hours old. Our variable speed pump seems to be losing prime as the water level in the pump strainer gets noticeably lower throughout the day. We mentioned it to our pool builder and he said the variable speed pumps run differently and aren’t always totally full to the window because it isn’t always running with full suction. It made sense at the time but we are seeing the water sometimes get almost as low as the intake hole. Is this normal or is something wrong?