Just a suggestion. Consider putting any anemones you get, into pvc end caps. They will attach their foot inside and you can place the end cap in the sand. Even if sand goes in the end cap almost all anemones are fine with this placement. I've almost never have one move out.
Check my build thread. I did an IM 10g anemone tank quite a while ago with a custom aquascape. It's still chugging along with happy healthy inhabitants more than a year later.