Thanks for the suggestions - here's an update for those following:

- I bought 2 cleaner shrimps. They survived a full week and then both died the same day. I tested the water and everything looked ok. It was at the start of the heat wave so maybe they weren't tollerant to the temp increase (it was up to almost 90f)

- I added a Blue Tang a few weeks back and he's doing quite well. Very active and eating often.

- As soon as I can find some I'll be adding 3-5 Bangaii Cardinals. That should be the end of the additions I think - should be close to fully stocked at that point.