While the tank is new to me (only about a month now) it was actually established about 6 or 7 years ago now. There's a fair amount of red bubble algae although it seems that no one is interested in eating that so I've been manually removing it with tweezers and a syphon. When I bought the tank, it only had a brittle star and a single hermit crab (and four fish).
The story behind how I ended up with the crew I have is this. My husband went to the LFS
and wanted to surprise me with a cleaning crew. The guy he spoke with said they recommend adding the crew in thirds, and sold him the following as the first "installment":
8 asstd tiny hermits
8 scarlet hermits
When I went back this weekend I talked to a different guy who didn't know anything about the "thirds" plan. So I asked for another sally, emerald, 5 peppermints, and 6 nassariuses. I skipped the hermits and trochuses because I felt like I had enough (and hadn't gotten around to posting the question here). Little did I know that I also had plenty of peppermints already!