We definitely recommend that you start with fine ground coffee if you just bought Happiels™ reusable coffee pods - then you can adjust tamping and how much coffee you put  into your pod.

Fine espresso blends will definitely be the right choice for you if you prefer your coffee strong. 

Use medium & coarse coffee grounds if you like your coffee less strong. These types of grinds definitely  require tamping, or otherwise your coffee might come out too watery and weak.