U can pretty much see as far as ur lites will. Lots to see at shallower. Top of the mound is about 80 so u could swim the perimeter of the cavern and still c light. 21% /Air. Safe mix/mod for 160 isnt really worth paying for to save 12 min of deco IMHO. Mixed gas is cool but the only way to economicaly dive it anymore is on a rebreather. Helium is crazy expensive gotta have deep pockets for mixed gas