You can’t balance between how much time you give to the personal and to the professional life. But you can always have harmony between two.
You don’t need to give eight hours to the family everyday but when you give time to the family, stay focused. Don’t attend business calls or check emails when you are with the family. That is what matters to them. Family don’t need your eight hours, they would be happy with two hours of focused time.
Not the balance, but harmony matters.