I am glad to hear the tang is doing well so far. Be wary of advice you get in shops. There are a lot of very helpful, knowledgeable people working in stores, but there are also a lot who are just looking to make a buck off of the inexperienced. So take anything you hear from them with caution, and look for second or third opinions. That is the great thing about a resource like this forum. You can learn from the experiences of other people, and we are all here because we love the hobby, not because we are trying to sell something. It looks like the parameters that your LFS tested in your water are fine for fish. However, that does not say anything about swings or spikes throughout the day and night or in the coming weeks. It takes time for your tank to settle, and it will take time for you to settle into a routine of dosing calcium and alkalinity. Personally, I like to wait about a month after the cycle finishes before adding a fish. But a lot of people can add fish sooner and be successful. Remember that every fish added puts more load on your biological filtration, and will take time for the bio filtration to catch up. So don't add too many fish at once, or too many in too short of a time. This is all relative to the size of your tank, though. Off the top of my head I would say wait at least 2 weeks between additions to your tank. As for right now, I would wait at least a month before adding any more fish to the tank. Also, in my experience I have found cleaner shrimp to be rather hardy for inverts, not more fragile than other inverts as you were told. This is why IMO if your tank is killing cleaner shrimp it is a danger to fish as well. Inverts like clams, anemones, and star fish are much more fragile than shrimp. Depending on your lighting, you might want to consider some easy corals as your next addition to your tank. Mushrooms or other soft corals are fairly tolerant of water conditions and can actually help stablilize your water. Anyway, remember to be patient before adding your next fish, and take this time to research the species you want to add and ask for people's advice on this forum. HTH