I have a frag of each, and unfortunately I've forgotten which is which. I can say they look different. One is just purple, the other has blues, and almost a hint of green tint, mixed in with the purple.
Here was my 30k I got from live aquaria. My understanding is the 20k has more green base color where the 30k is more cream base color. I unfortunately lost it in a tank crash last year.
I have the purple version..................don't have direct lineage to the named piece but I could care less. These are hard to find. Growth is verrrry slow.