It's been relatively slow. The second colony pictured has grown faster than the more upright one for some reason. I'd say that in five years, the upright one has maybe tripled in size (new upward growth being more prevalent than outward growth), where the more compact colony grew from a frag maybe three years ago. Not sure why the growth rates are so different, though. The upright one has been getting more light and more flow than the compact one (not sure what that tells us, though...).