I would keep an eye on your ammonia and nitrite levels. Moving a tank and stirring up a older sand bed can be disastrous, have new fresh salt water on hand to do water change. The tangs although fine now can get very aggressive towards new fish added in such a small tank, since there is not a lot of swimming space.
Rock work really is no set guideline just what ever you like to look at daily, don't expect to get it right the first time. Best way to do it is to have several tubs you can sort the rock out in. Large in one, medium and small in another. Then just make sure and stack it so that it is balanced and secure, last thing you want is a rock fall breaking the glass. Also if you plan to take the maroon out this would be a good time to do it. Find someone that ways to purchase it or a lfs can take to for store credit. Most people try and do caves with the rocks because it gives the fish places to hide and swim threw, most don't like just a big open swim area(tangs do) and want rocks to dart in and threw. Like I said it will take a few tries to get it right. I hate the way our rock work is at the moment but I'm not redoing it now because we are waiting on our contract to be accepted on a house purse and it will be moving any way.
Good luck and ask away on your questions lots of great people here full of information
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