Refugium stuff

[BCOrchidGuy]

I've got a refugium, 44 gallon, I have calupera, some live rock and a good 4 inch bed of aragonite sand. I've added some Mineral Mud and I was wondering what can I add to really get the aragonite seeded with life. I was thinking I should go to the LFS and get a few scoops of crud off the bottom of their LR aging buckets and tanks, but I wonder if there isn't a better way???
Any ideas?.....