Can't help you with Tulum particularly... maybe others can.
But if you're new to bones, you might consider our sponsor Randall Kaufmann's magnum opus on the topic. His book is regarded by many to be the ultimate contemporary work on the topic.
All I can say is prepare to develop a severe addiction. Not only do the fish themselves get into your blood but the whole package of airy turquoise waters, white coral sands and mangrove-lined tropical environs are hard to get out of one's mind once it's burned in!