Stage tank cave diving
Two scuba tanks is considered the safe minimum for cave diving. A trained cave diver that wants to go further into the cave will add additional tanks, called stage tanks, to their gear.
Cenote Vaca Ha is now open to cave divers after being closed for several years following a drowning in the nearby Cenote Tortuga. It is part of cave system Zapote which has nearly 8 kilometres of mapped passage.
As a cave diver moves into a cave they 'reference the cave' - a process of being aware of cave features so that you can verify you're on the correct path when you exit the cave. Monolithic formations like this one found upstream in Cenote Otoch Ha are unmistakeable road signs for cave divers.
Searching for salt water
On the east coast of Mexico's Yucatan Peninsula some cave systems connect to the ocean. Salt water intrudes from the sea into the caves. The depth at which you find the salt water in the cave varies depending on how close you are to the coast.