informal letter

Dear Sebastian
I ´m writing this letter to ask you some questions. To now about that potion that you created some time ago in London in your laboratory
I want to know:
What is the colour of the potion? How long the potion last? What changes on your body you have? How match do you drink? As you did the potion? What things do you use to do it? I will be waiting for your answer. Well, see you in my laboratory. If you came to my laboratory you can do the potion whit me