Hi all i thought i would treat myself recently so i purchased this broom style elm.

The tree is in a john pitt pot

What do people think should i keep the moss or replace it with a good top layer of akadama.

Moss is neither good nor bad. It could keep you from properly knowing when the soil should be watered but it can help keep the tree cool during summer. Leaving moss uncontrolled it can creep up the tree and discolor the bark. Really it's up to you. I use moss as a decorative piece for showes.