WP Cumulus Plugin Problem

Hi,

I am having some problems with the WP Cumulus Plugin.

If you look on my site, https://www.crystalgamer.com you will notice that some of the tags in the tag cloud in the sidebar are bigger than others.
(e.g ghostbusters).

I don’t know if this is based on popularity of the tags but if not please can someone tell me how to make them all the same size.

Many thanks