Menstrual cycle exceeds 10 days

Salaam, my menses exceed 10 days I follow the hanafi and do ghusl the next day which would be the 11th day but I am confused as to when the next day I normally do ghusl at midnight which is the next day to this world is this the correct way or do I do ghusl during dawn which in islam is considered the next day or do I perform ghusl during maghrib as that is also seen as the "next day"? which is the correct way? when do i perform ghusl after the 10 days?