Mushrooms,Leathers, and Polyps are easy to keep. Turbo Snails are ok, but tend to be big and can knock your corals over you don't have them cemented down.
i agree with those they can be kept with just about any type of lighting. some say 1 snail/gallon but if you get a good mix you dont need that many for my tank i have a 75 gall but i have
turbos, astrea, trochus, stomatella, nassarious and just as couple of each and they seem to keep up on the tank quite nicely. different snails eat different alges where the nassarous are scavengers and eat detrius and left over food. i also have a few peppermint snails but there so tiny i only see them at night and every once in a while. but it seems when 1 comes out they all do