The Rebreather Exploration and Research Organization

The Pit is a deep cave located in Tulum, Quintana Roo, Mexico. As part of the Dos Ojos cave system, the Pit is often visited by divers. Due to its extreme depth and the difficulties of conducting explorations in Mexico, however, the Pit has hardly been explored.

In 2009, the TRERO Dive Team visited the Pit and became addicted to its vast beauty. Over the next five years, the dive team began to systematically establish a base of operations in Tulum in order to conduct regular exploration dives into the Pit.

Follow our exploration of this wonderful cave through the videos and trip reports that are located below.

Exploring the Pit – Teaser

This video is a short teaser of the ongoing exploration Add Helium is performing at the Pit, part of the Dos Ojos cave system in Tulum, Mexico.

Exploring the Pit – Episode 1

Testing & Measuring

The Add Helium Dive Team conducts a series of checkout dives into the Pitt, part of the Dos Ojos cave system in Tulum, Quintana Roo Mexico. On this trip the team measured the guideline distances, as well as timing their simulated bailouts while swimming and scootering.

Exploring the Pit – Episode 2

Push the mainline – The Pit

On this dive, the Add Helium team attempts to scooter to the end of the mainline, and explore past it.


Exploring the Pit – Episode 3

Logistics of the Tortuga

How does a dive team explore a deep cave in Mexico? This 3-minute video offers a brief tour or the Tortuga – the base of operations for Add Helium’s ongoing exploration of The Pit, part of the Dos Ojos Cave System in Tulum Mexico.

Exploring the Pit – Episode 4

The Wakulla Room

In this episode, the team does a series of dives with the sole pupose of obtaining video footage from the Wakulla room.

Exploring the Pit – Episode 5

The Pit dive gear

The dive team discusses the dive gear they are using and why, shown with some previously unseen footage from inside the Pit.

On May 30, 2012, the Add Helium Dive Team conducted a dive to 652 feet off Grand Cayman’s West End. Divers Peter Sotis, and Kimberly Inge, along with a team of support divers, successfully completed the 6 hour dive using stock rEvo rebreathers.

This is a video highlight of all of their training, preparation and footage from the dive itself.

The dive was made possible by contributions and logistical support from Divetech, custom scooters from Submerge Scooters, dive computers from VR Technologies, safety equipment from Narked at 90, Light Monkey, and Hollis. Also Molecular Products, Pompano Dive Center, Reef Photo & Video, and Nauticam USA.

The dive was conducted on stock rEvo Rebreathers. Peter diving a rEvo III Micro FT, and Kimberly on a rEvo II Micro. Both rEvo’s utilized the stock orafice module and constant IP oxygen regulator. PO2 was maintained during the deep phase of the dive via off-board gas addition. Setup for this dive began the day prior, which involved placing a high-vis reference line along the wall, and staging multiple 80 cubic foot bottles of gas at various points. 32 aluminum 80 cylinders were staged or carried amongst the team to ensure that both deep divers would be able to surface after a catastrophic failure of their CCR’s.

Submerge Scooters of Jupiter Florida manufactured custom ‘deep’ scooters for this dive, which were a variant of the UV-18 lead acid model they currently offer. Among other modifications, super thick hull walls, and improved seals were installed to withstand the pressure of more than 20 atmospheres. Divers reported these scooters operated flawlessly throughout all phases of the dive.

Training for this dive included over 8 months of preparation, skill practice, team rehearsals, and deep bailouts, to include multiple bailout ascents from 450 feet, utilizing the Time to Surface method of PO2 averaging.

Both deep divers, and the 400 foot support team, along with other members of the team, embarked on an extreme physical fitness regimen, to include diet and exercise in order to raise cardiac output and efficiency, and lower body fat percentages. Kimberly’s body fat was measured by Dr. Pollock to be 11%, 2 days before the dive.

While water temperatures were in the high 80’s, due to the extended runtime, concerns about hypothermia were raised. Wetsuits and hooded vests were worn for exposure protection, along with heated westuit vests. Drysuits were considered, but ruled out

The video team entered the water at 9:45, followed by the deep divers and the 400 foot support team at 10:00 AM EST. Aside from some minor glitches with the deep safety divers, was uneventful for the entire 360 minute runtime.

The decompression algorithm for this dive was the VGM profile used by the VR Technologies VRx dive commuter. Post bubble scans of each diver conducted by Dr. Pollock at 20 minute intervals showed excellent results. Post dive examinations by Dr. Roussos were unremarkable, and and no signs of decompression illness were felt by either diver 48 hours late.