A few other options to enhance the biodiversity of your live sand. Split a bag of the commercial live sand with another member or check out the "Reef Grunge" from GARF. Someone here has an excess of microstars they are looking for a home for as well. They would be a good addition as well.

If you are going to be at the meeting, I can bring you a some amphipods (grammarus shrimp). I usually pick out a couple of dozen from my sock filters every time I clean them.