If you are considering getting Turbo snails, then you will need to make sure 100% that your rocks are secure. Also, if you have any coral or any frags, you will want those to be battened down as well. Turbo snails are known to push over decent sized rocks, when they want to get to something. If a piece of food falls between two rocks, the snail WILL try whatever it can to get to that piece of food, and that usually involves trying to get in between those rocks. The snails shell will shift the rocks as the snail tries to get to the food.. which could cause a rock slide which could leave you in a very bad situation, and possibly with saltwater soaked floors.
On another note, please take what i am about to say in to consideration because it will save you money and water quality.
Margarita snails are very nice snails, and they do their cleanup job rather well too. However, margarita snails originate from deeper water, and colder waters. When we harvest these snails to use for our tropical temperature aquariums, we are only doing ourselves more harm, and are killing innocent snails. When the margarita snail goes from its natural coldwater habitat, to these warm waters(78-84 dF), we are greatly reducing their lifespan. In the wild, or in cold water tanks, margarita snails can live a considerable amount of time; over 2 years. In our warm water tanks, their lifespan is drastically reduced to 1 year, most of the time less than that. It is in ours and the snails best interest to stay away from margarita snails, unless you have a cold water tank.. or you are a snail murderer. Either way, one of us is losing. So, in my opinion, and for the safety and longevity of these snails, please do not buy margarita snails if you have warm water tanks.
Anyways, emerald crabs are awesome, i have two. Cleaner shrimp are also awesome, i have one. I would definitely suggest astrea snails, trochus snails, and there's a couple other ones that i have forgotten their names. Also.. ANY sea star should not be put in to a tank that is not mature. Mature being a year old, or maybe 9 or 10 months old. Like anemones, Sea stars are also very sensitive to water fluctuations, and do not tolerate high nitrates or any type of copper medications. And unfortunately, in the early stages of a tank, wierd water flucts are a normality. Save your money, and save your tears. Just wait until your tank is mature, and then you can get the sea stars.